Genetics

Why is Autosomal Recessive Inheritance Important?

How are genes inherited? 

We have two copies of every gene in our bodies, inheriting one from our mother and one from our father, with the exception of genes on the male y chromosome which are only inherited paternally.

Autosomal Recessive Inheritance

Many genetic diseases are caused by changes or “variants” in a single gene. A variant can alter gene function or expression.  Whether or not people show signs of a genetic disease depends on how the disease is inherited. Autosomal recessive inheritance means the disease happens only when BOTH copies of the gene have a variant.  These types of diseases appear equally in both men and women. Most often these diseases are inherited from both parents who are “carriers”, also known as “heterozygotes”.

What does being a carrier mean?

Individuals who are carriers are usually healthy with no related symptoms of the disease.  Some carriers may have subtle or milder symptoms of the disease. It is not uncommon to be a carrier of at least one gene variant.

Why should you care?

When a person is a carrier, it is important to know if his/her reproductive partner is also a carrier. When two parents are carriers of a variant in the same gene, there is a 1 in 4 or 25% chance with each pregnancy of having a child affected with the disease. Relatives of a carrier also have an increased risk of being carriers of the variant.  Knowing about carrier status and potential risks of disease can be helpful in discussing family planning and reproductive testing options.

How do we use it in the Health Nucleus?

Through our whole genome sequence (WGS) analysis, we screen for medically significant variants in hundreds of genes, many of which follow autosomal recessive inheritance.  Examples of some of the more common autosomal recessive diseases that will be screened for through your WGS, include cystic fibrosis, sickle cell anemia, phenylketonuria (PKU) and Tay Sachs disease.  When you review your genetics report with one of our clinicians, you may be identified as a carrier of an autosomal recessive disease. This will be reported as a “Carrier Variant”.  It is not uncommon to be identified as a carrier of an autosomal recessive disease.

Where can I get additional information?

National Society of Genetic Counselors

Genetics Home Reference

Sources

Help Me Understand Genetics: National Library of Medicine (US).

Genetics Home Reference [Internet].

Bethesda (MD): The Library; 2018 Apr 3.

Inheriting Genetic Conditions; [cited 2018 Apr 3]