Answer to Question #278308 in Genetics for ram

Question

1)    Lesch-Nyhan syndrome is a metabolic defect caused by the lack of the enzyme hypoxanthine-guanine phosphoribosyl transferase (HGPRT). This disease is the result of an X-linked, recessive mutation and results in mental retardation, selfmutilation and early death. A normal man marries a woman who had a brother who died of LNS. Your are the genetic counselor who will advise them on the likelihood of their having a LNS baby.

a)     What are the possible genotypes for the woman? What is the man’s genotype?

b)    For each of the woman’s possible genotypes, what are the possible genotypes of her offspring and the implications for survival for each of them?

Answer 1

Lesch–Nyhan syndrome (LNS) is a rare inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). This deficiency occurs due to mutations in the HPRT1 gene located on the X chromosome. LNS affects about 1 in 380,000 live births.