X-linked–recessive inheritance

X-linked–recessive inheritance, a pattern of inheritance in which the transmission of a recessive allele on the X chromosome results in a carrier state in females and characteristics of an abnormal condition in males. Affected people have unaffected parents (except for the rare situation in which the father is affected and the mother is a carrier). One half of the female siblings of an affected male carry the trait. Unaffected male siblings do not carry the trait. Sons of affected males are unaffected, and daughters of affected males are carriers. Unaffected male children of a carrier female do not carry the trait. Compare X-linked–dominant inheritance.