What are autosomal recessive diseases?

Autosomal recessive diseases are genetic disorders caused by mutations in genes located on autosomes (non-sex chromosomes). These diseases are characterized by the inheritance pattern where both copies of the disease-causing gene must be present in an individual to manifest the disorder.

Key points about autosomal recessive diseases:

- Inheritance Pattern: In autosomal recessive disorders, an affected individual inherits one mutated copy of the disease gene from each parent who are carriers (heterozygous for the mutation). Carriers do not usually display symptoms as they have only one functional copy of the gene.

- Gene Frequency: Autosomal recessive diseases are relatively rare as both copies of the mutated gene must be present for the disease to manifest. However, the carrier frequency for these diseases can be relatively high in some populations due to the inheritance pattern.

- Homozygous Individuals: Individuals with two copies of the disease-causing mutation (homozygous for the recessive allele) are affected with the disorder.

- Parental Contribution: Both parents of an affected individual are typically carriers of one copy of the mutated gene. When both parents are carriers, each pregnancy has a 25% chance of producing an affected child, a 50% chance of producing unaffected carriers, and a 25% chance of producing unaffected individuals who do not carry the disease gene.

Examples of autosomal recessive diseases include cystic fibrosis, sickle cell anemia, Tay-Sachs disease, and Gaucher disease.