Tay-sachs Disease
Tay-Sachs disease occurs when the body lacks hexosaminidase A, a protein that helps break down a chemical found in nerve tissue called gangliosides. It is basically a recessive genetic disorder in children that causes destruction in the central nervous system. The condition is fatal. Since it's genetic, there is a possibility that the parent passes it on to the child and the child becomes the carrier. Every year at least 16 - 20 cases are detected with Tay-sachs disease.
There are three stages of Tay-Sachs, infantile, juvenile, and adult forms. Most have the infantile form. Here, the nerve damage usually begins while the baby is still in the womb. Symptoms usually appear when the child is 3 to 6 months old. The disease tends to get worse very quickly, as the child becomes blind, deaf, and unable to swallow and eventually becomes paralysed. Children usually die before they reach the age of 5 due to recurring infections.
Late-onset Tay-Sachs disease, in adults, is very rare.
Symptoms of Tay-sachs disease
Children with hearing, sight, and movement problems are tested for Tay-sachs disease. A physical exam and blood tests by the physician can identify the disease.
Babies with Tay-Sachs develop normally within the first 3 to 6 months and then during the next couple of months the baby will lose the ability to see, hear, and move.
Red spot will develop in the back of the child's eyes. The child will stop smiling, crawling, turning over, and reaching out for things and by the age of between 2 - 3 years the child may have seizures and become completely disabled. By the age of 5 the child usually dies. Tay-Sachs could only be prolonged if the child has the Hex A enzyme but usually the child can only survive only up to about 15 years.
Other symptoms include, laziness and delayed mental and social skills, Dementia, Irritability and Listlessness
Treatment can only prolong the inevitable. However, Doctors try to make the patient as comfortable as possible by treating the seizures and clearing the airway. Children may need to be tube fed after a certain stage and would need hospitalization and would be permitted to stay at home with a live-in health care provider.
Parents may find it difficult to deal with this condition. There are numerous support groups and physicians who are readily available to provide their service and advice to troubled parents.
Showing posts with label Genetic Disorders. Show all posts
Showing posts with label Genetic Disorders. Show all posts
Tuesday, June 24, 2014
Jewish Genetic Diseases
Jewish Genetic Diseases
Today, more than 4000 genetic diseases are known to affect humankind in a very negative way. The mystery of genetic diseases seems to wane as more and more people get to understand the basics of genetics better. The facts that people are continuing to get are proving to be very helpful by the day. The greatest mystery surrounding genetic diseases is the fact that they affect people of a particular family, ethnic group, race or demographic group. Against this backdrop, one can easily note that some diseases occur almost exclusively among the Jewish people.
Most genetic diseases that affect the Jewish people are incapacitating. A few of them have mild consequences on the patients' physical abilities. Tay-Sachs is the most commonly occurring genetic disease among the members of the Jewish community. This disease has mild negative effects, unlike many others, which are responsible for wiping out many Jewish families.
People who suffer from Jewish genetic diseases need to be taken care of in a very special way. Beta Thalassemia is a disease that is genetically transmitted among many Jews. This inherited disorder is also referred to as Cooley's anemia. Patients with this disease go through mutation of beta hemoglobin chain. No man can do anything in order to prevent this genetically triggered change from occurring.
Immediately after birth, a baby with Beta Thalassemia does no show any symptoms. This is because fetal hemoglobin is still the dominant element in the baby's blood. In a matter of months, everything changes and the symptoms come out. The condition starts worsening. Children develop anemia that is life threatening.
Bloom's Syndrome is a genetic disease that is also very common among Jews. It is transmitted through a recessive gene. In this case, both parents should be carriers of the recessive gene in order for the disease to be passed on to future generations. All victims of this disease have a very short stature and a very high-pitched voice. They are also highly susceptible to respiratory illnesses. People with Bloom's syndrome also tend to be mentally retarded.
The Bloom's Syndrome can be tested through chromosome analysis. Once this has been done, the diagnosis process can be said to be complete. In order for carrier testing to be done, a sample of a person's blood is needed. The test will ascertain whether any gene changes have occurred. This disease is very common among the Ashkenazi Jews.
Today, more than 4000 genetic diseases are known to affect humankind in a very negative way. The mystery of genetic diseases seems to wane as more and more people get to understand the basics of genetics better. The facts that people are continuing to get are proving to be very helpful by the day. The greatest mystery surrounding genetic diseases is the fact that they affect people of a particular family, ethnic group, race or demographic group. Against this backdrop, one can easily note that some diseases occur almost exclusively among the Jewish people.
Most genetic diseases that affect the Jewish people are incapacitating. A few of them have mild consequences on the patients' physical abilities. Tay-Sachs is the most commonly occurring genetic disease among the members of the Jewish community. This disease has mild negative effects, unlike many others, which are responsible for wiping out many Jewish families.
People who suffer from Jewish genetic diseases need to be taken care of in a very special way. Beta Thalassemia is a disease that is genetically transmitted among many Jews. This inherited disorder is also referred to as Cooley's anemia. Patients with this disease go through mutation of beta hemoglobin chain. No man can do anything in order to prevent this genetically triggered change from occurring.
Immediately after birth, a baby with Beta Thalassemia does no show any symptoms. This is because fetal hemoglobin is still the dominant element in the baby's blood. In a matter of months, everything changes and the symptoms come out. The condition starts worsening. Children develop anemia that is life threatening.
Bloom's Syndrome is a genetic disease that is also very common among Jews. It is transmitted through a recessive gene. In this case, both parents should be carriers of the recessive gene in order for the disease to be passed on to future generations. All victims of this disease have a very short stature and a very high-pitched voice. They are also highly susceptible to respiratory illnesses. People with Bloom's syndrome also tend to be mentally retarded.
The Bloom's Syndrome can be tested through chromosome analysis. Once this has been done, the diagnosis process can be said to be complete. In order for carrier testing to be done, a sample of a person's blood is needed. The test will ascertain whether any gene changes have occurred. This disease is very common among the Ashkenazi Jews.
Inherited Genetic Diseases
Inherited Genetic Diseases
It is important to have an insight into, and some knowledge about inherited genetic diseases, especially if one is planning to have a baby. Having sufficient knowledge can be of help in preventing the baby from acquiring such a disease.
Most birth related defects are usually inherited genetic diseases. This is normally a condition which leads to abnormalities in the structure and function of the baby right from birth. Often, these types of defects are genetic in nature, and are passed to the baby from the parents. However, some isolated cases may not be hereditary, and could be due to environmental hazards or external effects, exposed to the mother at pregnancy.
There are thousands of known inherited genetic diseases. Genetic diseases are varied in intensity and types. These may include physical conditions or defects, or delays in normal development of the child. Some inherited genetic diseases may be deadly. Sadly, all inherited genetic diseases cause a lot of physical and emotional pain both to the patient and to the parents.
Inherited genetic diseases can be passed down through various ways. They can be transmitted from the father, the mother or even both parents. In case where both parents have defaults in their genes, the defects are often inherited by the baby. On the other hand, where only one parent has a genetic defect, it is also possible for the defect to be passed on to the child. The other case is where the mother specifically passes on a genetic condition to the male offspring. This is a defect that affects only the X-chromosome. The baby is likely to have an inherited genetic disease if the X-chromosome of the mother is faulty.
Among the several common inherited genetic diseases include muscular diseases, usually inherited from the mother, and central nervous system defects - which may cause blindness, dementia and seizures. This is a dangerous and possibly fatal inherited genetic condition, especially if both parents have it. The other common condition is sickle cell anaemia, which is a disorder of the red blood cells. It can cause pain, fatigue and other health complications. The likelihood of the child inheriting this condition is higher if both parents carry the gene.
A basic precaution for parents to safeguard their unborn babies from acquiring inherited genetic diseases would be to maintain a healthy lifestyle and diet, especially for the mother throughout her pregnancy.
It is important to have an insight into, and some knowledge about inherited genetic diseases, especially if one is planning to have a baby. Having sufficient knowledge can be of help in preventing the baby from acquiring such a disease.
Most birth related defects are usually inherited genetic diseases. This is normally a condition which leads to abnormalities in the structure and function of the baby right from birth. Often, these types of defects are genetic in nature, and are passed to the baby from the parents. However, some isolated cases may not be hereditary, and could be due to environmental hazards or external effects, exposed to the mother at pregnancy.
There are thousands of known inherited genetic diseases. Genetic diseases are varied in intensity and types. These may include physical conditions or defects, or delays in normal development of the child. Some inherited genetic diseases may be deadly. Sadly, all inherited genetic diseases cause a lot of physical and emotional pain both to the patient and to the parents.
Inherited genetic diseases can be passed down through various ways. They can be transmitted from the father, the mother or even both parents. In case where both parents have defaults in their genes, the defects are often inherited by the baby. On the other hand, where only one parent has a genetic defect, it is also possible for the defect to be passed on to the child. The other case is where the mother specifically passes on a genetic condition to the male offspring. This is a defect that affects only the X-chromosome. The baby is likely to have an inherited genetic disease if the X-chromosome of the mother is faulty.
Among the several common inherited genetic diseases include muscular diseases, usually inherited from the mother, and central nervous system defects - which may cause blindness, dementia and seizures. This is a dangerous and possibly fatal inherited genetic condition, especially if both parents have it. The other common condition is sickle cell anaemia, which is a disorder of the red blood cells. It can cause pain, fatigue and other health complications. The likelihood of the child inheriting this condition is higher if both parents carry the gene.
A basic precaution for parents to safeguard their unborn babies from acquiring inherited genetic diseases would be to maintain a healthy lifestyle and diet, especially for the mother throughout her pregnancy.
Human Genetic Diseases
Human Genetic Diseases
The main reason why genetic diseases are a cause of worry for many people is the fact that man can do little to prevent them from occurring. Genetic diseases occur because of chromosome problems. Some genetic diseases are extremely rare while others occur more often.
Some genetic diseases relate to one's reproductive health. Recent research has also shown that some genetic diseases are gender-driven, that is, they affect members of one gender only. A case in point is color blindness, which is known to affect male members of a community only.
Researchers have devised several ways of drawing ethnic, racial and demographic lines when researching on human genetic diseases. When researching the Alzheimer's disease, scientists had to rely on a previous finding, which showed that very few cases of the disease are reported among the Caucasian people.
The Alzheimer's disease can bring rather catastrophic effects to both the patients and loved ones. It affects the brain and makes the patient lose memory and psychomotor coordination. The patient loses complete control of all his bodily functions. One does not even remember to eat. If food is put into his mouth, he does not know when to chew and when to swallow. Such patients require special care, often in a nursing home. Majority of people who are affected are over sixty years.
DNA tests are always helpful in determining if any member of the family is a carrier of a dominant gene. Some genetic diseases are caused by dominant genes. In some cases, recessive genes also cause genetic disorders. In families where the genetic disorders are caused by a dominant gene, if the parent has the disease, the sibling has a 50% likelihood of suffering from the same disease at some point in life.
The process of diagnosing genetic disorder is very complicated. As if that is not enough, one has to take care of the patient both financially and psychologically. This might drain a family's financial resources. It can also make one marriage partner feel emotionally detached. Help from third parties would be very much appreciated.
Many support groups for people who suffer from genetic disorders have been set up across the country. A person who suffers from a genetic condition can reap many benefits by becoming a member of such a group. One can get to know how to pursue treatment. One can get to regain a feeling of belonging after depressive moments especially immediately after diagnosis.
The main reason why genetic diseases are a cause of worry for many people is the fact that man can do little to prevent them from occurring. Genetic diseases occur because of chromosome problems. Some genetic diseases are extremely rare while others occur more often.
Some genetic diseases relate to one's reproductive health. Recent research has also shown that some genetic diseases are gender-driven, that is, they affect members of one gender only. A case in point is color blindness, which is known to affect male members of a community only.
Researchers have devised several ways of drawing ethnic, racial and demographic lines when researching on human genetic diseases. When researching the Alzheimer's disease, scientists had to rely on a previous finding, which showed that very few cases of the disease are reported among the Caucasian people.
The Alzheimer's disease can bring rather catastrophic effects to both the patients and loved ones. It affects the brain and makes the patient lose memory and psychomotor coordination. The patient loses complete control of all his bodily functions. One does not even remember to eat. If food is put into his mouth, he does not know when to chew and when to swallow. Such patients require special care, often in a nursing home. Majority of people who are affected are over sixty years.
DNA tests are always helpful in determining if any member of the family is a carrier of a dominant gene. Some genetic diseases are caused by dominant genes. In some cases, recessive genes also cause genetic disorders. In families where the genetic disorders are caused by a dominant gene, if the parent has the disease, the sibling has a 50% likelihood of suffering from the same disease at some point in life.
The process of diagnosing genetic disorder is very complicated. As if that is not enough, one has to take care of the patient both financially and psychologically. This might drain a family's financial resources. It can also make one marriage partner feel emotionally detached. Help from third parties would be very much appreciated.
Many support groups for people who suffer from genetic disorders have been set up across the country. A person who suffers from a genetic condition can reap many benefits by becoming a member of such a group. One can get to know how to pursue treatment. One can get to regain a feeling of belonging after depressive moments especially immediately after diagnosis.
Monday, June 23, 2014
Genetic Testing Disease
Genetic Testing Disease
Genetic testing of a disease is a method of screening the person for possibility of inheritance factors that may point to the fact that an individual is likely to suffer from a disease that may have infected other members of the family. Naturally each and every individual inherits two different genes from each of the parents. In the process of inheriting these genes, a new born may as well inherit some of the hereditary complications that may have been prevalent in any of the parents' lineage. In normal circumstances, a person is screened for the presence of mutant genes which are capable of mutating and developing into the potential disease coursing pathogens.
There are different types of genetic testing that are used to determine different conditions in any individual. Some of the main types of genetic testing are; Newborn screening, diagnostic testing, carrier testing, pre-implantation genetic diagnosis and predictive and pre-symptomatic testing. In order to get a clear understanding of the above types of genetic tests, lets have a step by step definition of each an its significance in our lives.
Newborn screening
Newborn screening is a genetic type of test carried out to verify any early traces of gene related complications that may cause health disorders in future. There are certain genetic disorders such as phenylketonuria which if left unattended to results in mental disorders in the victim. This screening has become one of the most common genetic tests carried out especially in the U.S.
Diagnostic testing
This type of genetic screening is used more often in cases where a known genetic disorder has been proved to be present in one of the parents. It is usually carried out with the sole objective of identifying and taking preventive action towards the suspected gene should it be verified to be a potential risk. As much as the genetic disorders may not all be treatable, knowing their existence helps a great deal in helping the individual in managing any problems that may occur as a result of the genetic condition.
Carrier testing
Carrier testing is simply used to identify persons who carry a particular form of mutating gene that could easily result in the occurrence of genetic diseases if coupled with a complementary gene. This testing can go a long way in helping to match couples who have potential risks of producing off springs who may be affected by their genetic condition.
Pre-implantation genetic diagnosis
Knowing the unborn child's genetic status is of great importance in making important decisions that may save the unborn baby's future possibility of developing genetic based complications. As technological improvements in in-vitro fertilization continue to take effect, the importance of pre-implantation genetic diagnosis cannot be taken for granted. Knowing the possibility of the matched embryos is important if the resulting fetus is to be free of most genetic based complications.
Genetic testing of a disease is a method of screening the person for possibility of inheritance factors that may point to the fact that an individual is likely to suffer from a disease that may have infected other members of the family. Naturally each and every individual inherits two different genes from each of the parents. In the process of inheriting these genes, a new born may as well inherit some of the hereditary complications that may have been prevalent in any of the parents' lineage. In normal circumstances, a person is screened for the presence of mutant genes which are capable of mutating and developing into the potential disease coursing pathogens.
There are different types of genetic testing that are used to determine different conditions in any individual. Some of the main types of genetic testing are; Newborn screening, diagnostic testing, carrier testing, pre-implantation genetic diagnosis and predictive and pre-symptomatic testing. In order to get a clear understanding of the above types of genetic tests, lets have a step by step definition of each an its significance in our lives.
Newborn screening
Newborn screening is a genetic type of test carried out to verify any early traces of gene related complications that may cause health disorders in future. There are certain genetic disorders such as phenylketonuria which if left unattended to results in mental disorders in the victim. This screening has become one of the most common genetic tests carried out especially in the U.S.
Diagnostic testing
This type of genetic screening is used more often in cases where a known genetic disorder has been proved to be present in one of the parents. It is usually carried out with the sole objective of identifying and taking preventive action towards the suspected gene should it be verified to be a potential risk. As much as the genetic disorders may not all be treatable, knowing their existence helps a great deal in helping the individual in managing any problems that may occur as a result of the genetic condition.
Carrier testing
Carrier testing is simply used to identify persons who carry a particular form of mutating gene that could easily result in the occurrence of genetic diseases if coupled with a complementary gene. This testing can go a long way in helping to match couples who have potential risks of producing off springs who may be affected by their genetic condition.
Pre-implantation genetic diagnosis
Knowing the unborn child's genetic status is of great importance in making important decisions that may save the unborn baby's future possibility of developing genetic based complications. As technological improvements in in-vitro fertilization continue to take effect, the importance of pre-implantation genetic diagnosis cannot be taken for granted. Knowing the possibility of the matched embryos is important if the resulting fetus is to be free of most genetic based complications.
Genetic Disease List
Genetic Disease List
Mutation, deletion, aberrations, unusual extension of genes causes genetic diseases. As medical scientists still do not know of ways to stop genetic disorders prior to birth, many children are born with genetic disorders.
Angelman Syndrome is one of rare genetic diseases. In 1965 Dr. Angelman first described the details of this neuro-genetic disorder, in which growth delaying, difficulty in speaking, sleeping disorders and mood swings are common symptoms.
Canavan disease genetically destructs the brain cells. It belongs to the genetic disease category called leukodystrophies. Its main characteristic is the degeneration of myelin, which is the protecting layer of nerve fibers of the body.
Celiac disease affects the autoimmune system damaging the small bowel. From infancy to any age group, this disease can be harmful. The main symptoms are fatigue and diarrhoea. Those who suffer from Celiac disease have difficulties in nutrient absorption abilities. An effective treatment for Celiac disease is a gluten-free diet.
Charcot-Marie-Tooth disease is a heterogeneous genetic disorder of nerves which is defined by touch sensation and loss of muscle tissue, especially in the legs and feet, but in the arms and hands as well in the advanced phases of disease.
Color blindness, or deficiency to perceive colors can be of a genetic nature, but can as well appear because of brain, eye, or nerve damage, or because of contact with some chemicals products. In 1798, the English chemist John Dalton studied this aspect for the first time. It is sometimes called daltonism after him.
Cri du Chat syndrome is a rare genetic disorder which affects approximately 1 in 20,000 to 50,000 live births. The disease does not depend on ethnic backgrounds, but is most common in the case of women.
The disorder gets its name from the typical cry of babies born with this syndrome. The baby sounds like a kitten, because of problems with the nervous system and larynx. The good news is that about 1/3 of infants recover by the age of 2. Negative aspects of this disease may be:
1. Feeding problems because they can't suck and swallow well
2. Low weight at birth and poor evolution,
3. Motor, cognitive, and speech delays,
4. Behavioral problems such as aggression, hyperactivity, and repetitive movements,
5. Uncommon facial traits that can change in time.
Cystic fibrosis is an inherited disorder which can affect the entire body, leading to gradual disability and death.
The most common symptoms are difficulty breathing and not enough enzyme production in the pancreas. Low immune system and dense mucous production lead to frequent lung infections that are treated, but not always cured, sometimes by intravenous and oral antibiotics. Many other symptoms, like sinus infections, poor evolution, and diarrhea can be effects of this disorder. Sometimes, recurrent lung infections during infancy or childhood may be a sign of cystic fibrosis.
Down syndrome is a hereditary disorder which features problems related to cognitive ability, physical evolution, and facial traits. It is called after John Langdon Down, the doctor who described it in 1866, in Britain.
Duchenne muscular dystrophy is a mortal disorder which is defined by rapidly gradual muscle weakness and damaged muscular tissue beginning in the pelvis and legs and then affecting the entire system.
Hemophilia is the name of some genetic disorders which mean the body's inability to control bleeding. The bleeding might be exterior, if the skin is broken by a cut, scrape, or abrasion, or it can be interior, into joints, muscles, or organs which are hollow. The result can be visible on the skin or subtle (e.g., brain bleeding).
Klinefelter syndrome has in main effect abnormal testicular evolution and decreased fertility.
Neurofibromatosis includes a more different genetic disorder which makes tumors develop along different nerves, besides, may influence the evolution of tissues which are not nervous, like skin and bones. The tumors may develop anywhere in or on the body.
The list may continue with other genetic disorders like: Phenylketonuria, Prader-Willi syndrome, Sickle-cell disease, Spina bifida, Tay-Sachs disease or Turner syndrome.
Unfortunately the list does not finish here and researchers in the domain of medicine must work a lot harder in order to discover remedies for them.
Mutation, deletion, aberrations, unusual extension of genes causes genetic diseases. As medical scientists still do not know of ways to stop genetic disorders prior to birth, many children are born with genetic disorders.
Angelman Syndrome is one of rare genetic diseases. In 1965 Dr. Angelman first described the details of this neuro-genetic disorder, in which growth delaying, difficulty in speaking, sleeping disorders and mood swings are common symptoms.
Canavan disease genetically destructs the brain cells. It belongs to the genetic disease category called leukodystrophies. Its main characteristic is the degeneration of myelin, which is the protecting layer of nerve fibers of the body.
Celiac disease affects the autoimmune system damaging the small bowel. From infancy to any age group, this disease can be harmful. The main symptoms are fatigue and diarrhoea. Those who suffer from Celiac disease have difficulties in nutrient absorption abilities. An effective treatment for Celiac disease is a gluten-free diet.
Charcot-Marie-Tooth disease is a heterogeneous genetic disorder of nerves which is defined by touch sensation and loss of muscle tissue, especially in the legs and feet, but in the arms and hands as well in the advanced phases of disease.
Color blindness, or deficiency to perceive colors can be of a genetic nature, but can as well appear because of brain, eye, or nerve damage, or because of contact with some chemicals products. In 1798, the English chemist John Dalton studied this aspect for the first time. It is sometimes called daltonism after him.
Cri du Chat syndrome is a rare genetic disorder which affects approximately 1 in 20,000 to 50,000 live births. The disease does not depend on ethnic backgrounds, but is most common in the case of women.
The disorder gets its name from the typical cry of babies born with this syndrome. The baby sounds like a kitten, because of problems with the nervous system and larynx. The good news is that about 1/3 of infants recover by the age of 2. Negative aspects of this disease may be:
1. Feeding problems because they can't suck and swallow well
2. Low weight at birth and poor evolution,
3. Motor, cognitive, and speech delays,
4. Behavioral problems such as aggression, hyperactivity, and repetitive movements,
5. Uncommon facial traits that can change in time.
Cystic fibrosis is an inherited disorder which can affect the entire body, leading to gradual disability and death.
The most common symptoms are difficulty breathing and not enough enzyme production in the pancreas. Low immune system and dense mucous production lead to frequent lung infections that are treated, but not always cured, sometimes by intravenous and oral antibiotics. Many other symptoms, like sinus infections, poor evolution, and diarrhea can be effects of this disorder. Sometimes, recurrent lung infections during infancy or childhood may be a sign of cystic fibrosis.
Down syndrome is a hereditary disorder which features problems related to cognitive ability, physical evolution, and facial traits. It is called after John Langdon Down, the doctor who described it in 1866, in Britain.
Duchenne muscular dystrophy is a mortal disorder which is defined by rapidly gradual muscle weakness and damaged muscular tissue beginning in the pelvis and legs and then affecting the entire system.
Hemophilia is the name of some genetic disorders which mean the body's inability to control bleeding. The bleeding might be exterior, if the skin is broken by a cut, scrape, or abrasion, or it can be interior, into joints, muscles, or organs which are hollow. The result can be visible on the skin or subtle (e.g., brain bleeding).
Klinefelter syndrome has in main effect abnormal testicular evolution and decreased fertility.
Neurofibromatosis includes a more different genetic disorder which makes tumors develop along different nerves, besides, may influence the evolution of tissues which are not nervous, like skin and bones. The tumors may develop anywhere in or on the body.
The list may continue with other genetic disorders like: Phenylketonuria, Prader-Willi syndrome, Sickle-cell disease, Spina bifida, Tay-Sachs disease or Turner syndrome.
Unfortunately the list does not finish here and researchers in the domain of medicine must work a lot harder in order to discover remedies for them.
Common Genetic Disease
Common Genetic Disease
It is since two decade that there is an increasing awareness of the importance of genetic factors in the aetiology and pathogenesis of many disorders affecting man. Perhaps of most importance, is that this knowledge has also led the possible means of prevention of such disorders through genetic counselling and antenatal diagnosis.
Down's syndrome:
This occurs in about once in 700 live-births and is characterized by flat face with widely spaced and upward slanting eyes, epicanthic folds, brachycephaly, malformed ears broad and/or short neck and a single transverse palmer crease. Patients with Down's syndrome are invariably mentally retarded, but have a pleasant, quite personally and show a great fondness for music. About 1% of cases of Down's syndrome are mosaics, that is, they possess two different cell lines, one of which has a normal chromosome constitution, the other an extra chromosome 21. This arises as result of non-disjunction occurring at or after the first zygotic division and is very rarely inherited. The clinical picture may often be considerably modified in some of these cases.
Turner's syndrome: this was the first sex chromosome aneuploidy to be described in females. An XO sex chromosome constitution is the commonest abnormality and also arises by non-disjunction, but unlike Klinefelter's syndrome, Turner's syndrome does not show relationship with maternal age. Turner's syndrome may also result from isochromosomes, deletions and rings involving the X chromosome. The main clinical features of Klinefelter's Turner's syndrome are listed respectively, Sterility, small testes, Eunuchoid body proportions, Gynaeco mastia, Mental retardation and primary amenorrhoea, Sterility, Lack of secondary sexual characteristics, short stature and various congenital abnormalities.
Genetics of Haemophilia A: The factor VIII gene is localised on the X chromosome making haemophilia A, a sex linked disorder. Thus on pedigree grounds all daughters of haemophilia are obligate carriers and sisters have 50% chance of being a carrier. If a carrier has a son, he has 50% chance of haemophilia, and daughter has 50% chance of being a carrier. Haemophilia 'breeds true' within a family, as all members will have the same abnormality of a factor VIII gene, i.e. if one individual has severe haemophilia all other affected will also have a severe form of the disorder. Female carriers of haemophilia tend to have a reduced factor VIII levels because of random inactivation of the X chromosome in developing foetus. An indication of carrier ship can be ascertained by measurement of factor VIIIC: von Willebrand factor (vWF) ratio is reduced in carrier compared to normal individuals.
It is since two decade that there is an increasing awareness of the importance of genetic factors in the aetiology and pathogenesis of many disorders affecting man. Perhaps of most importance, is that this knowledge has also led the possible means of prevention of such disorders through genetic counselling and antenatal diagnosis.
Down's syndrome:
This occurs in about once in 700 live-births and is characterized by flat face with widely spaced and upward slanting eyes, epicanthic folds, brachycephaly, malformed ears broad and/or short neck and a single transverse palmer crease. Patients with Down's syndrome are invariably mentally retarded, but have a pleasant, quite personally and show a great fondness for music. About 1% of cases of Down's syndrome are mosaics, that is, they possess two different cell lines, one of which has a normal chromosome constitution, the other an extra chromosome 21. This arises as result of non-disjunction occurring at or after the first zygotic division and is very rarely inherited. The clinical picture may often be considerably modified in some of these cases.
Turner's syndrome: this was the first sex chromosome aneuploidy to be described in females. An XO sex chromosome constitution is the commonest abnormality and also arises by non-disjunction, but unlike Klinefelter's syndrome, Turner's syndrome does not show relationship with maternal age. Turner's syndrome may also result from isochromosomes, deletions and rings involving the X chromosome. The main clinical features of Klinefelter's Turner's syndrome are listed respectively, Sterility, small testes, Eunuchoid body proportions, Gynaeco mastia, Mental retardation and primary amenorrhoea, Sterility, Lack of secondary sexual characteristics, short stature and various congenital abnormalities.
Genetics of Haemophilia A: The factor VIII gene is localised on the X chromosome making haemophilia A, a sex linked disorder. Thus on pedigree grounds all daughters of haemophilia are obligate carriers and sisters have 50% chance of being a carrier. If a carrier has a son, he has 50% chance of haemophilia, and daughter has 50% chance of being a carrier. Haemophilia 'breeds true' within a family, as all members will have the same abnormality of a factor VIII gene, i.e. if one individual has severe haemophilia all other affected will also have a severe form of the disorder. Female carriers of haemophilia tend to have a reduced factor VIII levels because of random inactivation of the X chromosome in developing foetus. An indication of carrier ship can be ascertained by measurement of factor VIIIC: von Willebrand factor (vWF) ratio is reduced in carrier compared to normal individuals.
A Genetic Disease
A Genetic Disease
A genetic disease refers to any disease that is caused by an unusual status in a particular person's genome. The disorder or abnormality in the genome may be minor or major depending on the amount of mutations in a single DNA base. There are several types of genetically inherited problems and each has its different features. Some of the main types of genetic inheritance are discussed here bellow.
Single gene inheritance
This kind of inheritance results from mutations that take place within the DNA sequence of one gene. This type of gene is more predictable as it always follows a particular trend and its destiny is therefore easy to predict. It is responsible for disorders such as sickle cell anemia, Huntington's disease and Marfan syndrome among other conditions.
Multifactorial inheritance
Commonly referred to as complex inheritance, this type of inheritance is usually caused by multiple environmental conditions which may mutate in various genes within a cell. These kind of inheritable genes are responsible for most chronic disorders such as high blood pressure, diabetes, arthritis among others. It has been established that this types of genes are also responsible for the similarities evident in identical personal traits such as fingerprint patterns, height, and eye and skin color among other similarities that are passed on from parent to child.
Genetic diseases and the human genome
It would be absolutely impossible to talk about the relationship between genetics and disease without considering the role played by the human genome or its influence on the diseases that are gene related. When you talk about any hereditary factor between two human beings, the most important feature that comes to mind is the human genome which is the bank of all inheritable traits in the human body and mind. A person's genes play a major role in the way a person's body reacts to environmental factors such as allergies and other specific preferences. It is out of this reason that most members of a particular family may suffer from similar diseases especially if the diseases are genetic in nature.
Illnesses such as diabetes can have their roots in a certain family affecting almost all family members and without the support of this type of information; it might seem quite intriguing that all members of a family should suffer the same disease. The answer lies in the relationship between the disease and the genes that have been inherited from the family lineage.
A genetic disease refers to any disease that is caused by an unusual status in a particular person's genome. The disorder or abnormality in the genome may be minor or major depending on the amount of mutations in a single DNA base. There are several types of genetically inherited problems and each has its different features. Some of the main types of genetic inheritance are discussed here bellow.
Single gene inheritance
This kind of inheritance results from mutations that take place within the DNA sequence of one gene. This type of gene is more predictable as it always follows a particular trend and its destiny is therefore easy to predict. It is responsible for disorders such as sickle cell anemia, Huntington's disease and Marfan syndrome among other conditions.
Multifactorial inheritance
Commonly referred to as complex inheritance, this type of inheritance is usually caused by multiple environmental conditions which may mutate in various genes within a cell. These kind of inheritable genes are responsible for most chronic disorders such as high blood pressure, diabetes, arthritis among others. It has been established that this types of genes are also responsible for the similarities evident in identical personal traits such as fingerprint patterns, height, and eye and skin color among other similarities that are passed on from parent to child.
Genetic diseases and the human genome
It would be absolutely impossible to talk about the relationship between genetics and disease without considering the role played by the human genome or its influence on the diseases that are gene related. When you talk about any hereditary factor between two human beings, the most important feature that comes to mind is the human genome which is the bank of all inheritable traits in the human body and mind. A person's genes play a major role in the way a person's body reacts to environmental factors such as allergies and other specific preferences. It is out of this reason that most members of a particular family may suffer from similar diseases especially if the diseases are genetic in nature.
Illnesses such as diabetes can have their roots in a certain family affecting almost all family members and without the support of this type of information; it might seem quite intriguing that all members of a family should suffer the same disease. The answer lies in the relationship between the disease and the genes that have been inherited from the family lineage.
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