Question

Fatty acid metabolism disorder is an autosomal recessive disorder. Two unaffected parents have 6 children - 4 of whom are affected, and 2 of whom are unaffected.

What are the chances that this couple will have a heterozygous child?

Answer 1

Fatty acid metabolism is autosomal recessive disorder, thus to express the disorder , both the alleles has express recessive gene . As the parents have both affected and non-affected children, the parents has to be heterozygous dominant.

lets assume the dominant allele is A and recessive allele is a

Aa X Aa

	A	a
A	AA unaffected	Aa unaffecetd
a	Aa unaffected	aa affected

hus there is a 50% chance that the couple will have heterozygous genotype (Aa), which is unaffected for the disorder.