Definition. Sex-linked diseases are passed down through families through one of the X or Y chromosomes. X and Y are sex chromosomes. Dominant inheritance occurs when an abnormal gene from one parent causes disease even though the matching gene from the other parent is normal.The abnormal gene dominates.efinition. Sex-linked diseases are passed down through families through one of the X or Y chromosomes. X and Y are sex chromosomes. Dominant inheritance occurs when an abnormal gene from one parent causes disease even though the matching gene from the other parent is normal.
Savant syndrome is a rare syndrome in which people with poor mental development or brain injury possess extraordinary mental skills which are difficult to explain scientifically. Sometimes the talents of a savant may go unnoticed.he exact cause of a savant syndrome is not known. A lot of hypotheses have been proposed. Some researchers believe that there is damage to the left hemisphere of brain, which results in compensatory changes in the right side of brain.
1 Prader-Willi syndrome is caused by the loss of genes in a specific region of chromosome 15, though it is not usually inherited. 2  People with Prader-Willi syndrome typically have mild to moderate intellectual impairment and learning disabilities.