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The following is a list of genetic disorders and if known, type of mutation and for the chromosome involved. Although the parlance "disease-causing gene" is common, it is the occurrence of an abnormality in the parents that causes the impairment to develop within the child. There are over 6,000 known genetic disorders in humans.
Trisomy 18, also known as Edwards syndrome, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18. [3] Many parts of the body are affected. [ 3 ] Babies are often born small and have heart defects . [ 3 ]
X-linked intellectual disability refers to medical disorders associated with X-linked recessive inheritance that result in intellectual disability. As with most X-linked disorders, males are more heavily affected than females. [1] Females with one affected X chromosome and one normal X chromosome tend to have milder symptoms.
An example of a condition that appears to have very little if any genetic influence is irritable bowel syndrome (IBS), with a concordance of 28% vs. 27% for MZ and DZ pairs respectively. [26] An example of a human characteristics that is extremely heritable is eye color, with a concordance of 98% for MZ pairs and 7–49% for DZ pairs depending ...
These traits vary in severity; though some women with trisomy X are significantly impaired, many are within the normal range of variance, and some are high-functioning and high-achieving. [ 16 ] Some mental health issues are more frequent in women with trisomy X. Dysthymia and cyclothymia , milder forms of depression and bipolar disorder ...
An example of a family pedigree displaying an autosomal recessive trait. A pedigree is a diagram showing the ancestral relationships and transmission of genetic traits over several generations in a family. Square symbols are almost always used to represent males, whilst circles are used for females.
Many causes of autism, including environmental and genetic factors, have been recognized or proposed, but understanding of the theory of causation of autism is incomplete. [1] Attempts have been made to incorporate the known genetic and environmental causes into a comprehensive causative framework. [2]
It was purely by chance that nearly thirty years ago (e.g. , circa 1964) three handicapped children were admitted at various times to my children's ward in England. They had a variety of disabilities and although at first sight they seemed to be suffering from different conditions I felt that there was a common cause for their illness.