obligate heterozygote

An individual who must be heterozygous for a variant based on analysis of the family history; applies to disorders inherited in an autosomal recessive or X-linked manner. The term "obligate heterozygote" can also refer to individuals with an autosomal dominant disorder whose position in a pedigree indicates that they must be heterozygous even though they do not manifest the phenotype.

Related terms: autosomal dominant; autosomal recessive; carrier; heterozygote; X-linked