Library · Genetics
Carrier of a genetic disease
Make it clearer
Being a carrier of a genetic disease means carrying a variant, that is, a change in a gene, linked to a disease inherited in an autosomal recessive or sex-linked pattern, without having any symptoms of that disease.
This happens because we have two copies of every gene, one from each parent. The carrier got the copy with the variant from one of them and the normal copy from the other. For some genes, a single working copy is enough. Think of two copies of the same key: as long as one works, the door opens.
The situation changes when two carriers of the same autosomal recessive disorder have a child together. If that child gets the nonworking copy from each of them, that is when the problem shows up.
And it usually goes unnoticed: most of the time, nobody knows they are a carrier.
In brief
A carrier has a genetic variant for an autosomal recessive or sex-linked disease and shows no symptoms of that disease.
They inherited the variant allele from one parent and the normal one from the other; for some genes one working copy is enough.
Two copies of the same key, and the door opens if just one of them works.
Trouble arises when both parents carry the same autosomal recessive disorder and the child receives both nonworking copies.
Most of the time, no one knows they are a carrier.
Sources (1)
- National Human Genome Research InstituteCarrier, Talking Glossary of Genomic and Genetic TermsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated