An individual who is heterozygous for a recessive disorder is called a carrier. This means they have one normal (dominant) allele and one mutated (recessive) allele for the disorder. Because the disorder is recessive, the dominant normal allele masks the effect of the recessive mutated allele, so the carrier does not typically show symptoms of the disorder. However, they can pass the recessive allele to their offspring, who may develop the disorder if they inherit two recessive alleles (one from each parent)
. In summary:
- Heterozygous means having two different alleles at a gene locus.
- For a recessive disorder, a heterozygous individual carries one mutated allele but usually does not express the disorder.
- Such an individual is referred to as a carrier of the recessive disorder
