Question

3) Lowe syndrome is a rare genetic condition that causes physical and mental handicaps and medical problems. It was first described in 195 involved (eyes, brain and kidney) it is known as OCRL (oculo-cerebro-renal) syndrome. Boys with Lowe syndrome are born with cataracts in both eyes which are usually removed at a few months of age. Glaucoma is present in about 50% of the boys with Low syndrome, though usually not at birth. Slowly progressive renal failure is the major cause of mortality, with death usually occurring in the second or third decade of life. About 1/3 of patients have profound mental retardation, but most have IQ's in the moderate range of 40-54. It is a hereditary condition that affects only males, caused by a single defective gene in a gene called OCRL1 Because of this defective gene an essential enzyme called PIP2-5-phosphatase is not produced. This enzyme is localized in the Golgi apparatus and appears to play a role i cellular trafficking. Deficiency of this enzyme may impair proper cellular protein sorting. A normal man and a normal woman have had one male child who died of Lowe syndrome What is the probability that their next child will be affected with the syndrome?

Answer 1