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.
Piriformis syndrome is an uncommon neuromuscular disorder caused by the compression or irritation of the sciatic nerve by the piriformis muscle. It results in pain in the buttocks and the leg and it is an unusual cause of sciatica.It is often misdiagnosed or unrecognised in patients with lower back pain.ommon causes of piriformis syndrome include: 1  Long-distance walking or running (overuse of the piriformis muscle). 2  Direct compression of the piriformis muscle (repetitive trauma). 3  Direct trauma to the buttocks resulting in sciatic nerve compression.