What is Autosomal Recessive Inheritance?
Autosomal recessive inheritance is a pattern of genetic transmission where two copies of a mutated gene, one from each parent, are necessary to cause a particular genetic disorder. These genes are located on one of the 22 pairs of
autosomes, which are chromosomes that are not sex chromosomes. For an individual to express an autosomal recessive disorder, they must inherit one defective gene from each parent.
How Does Autosomal Recessive Inheritance Work?
Each individual has two copies of most genes, one inherited from each parent. In autosomal recessive inheritance, both copies of a gene must be altered or mutated for a person to exhibit symptoms of the disorder. Individuals who have only one mutated gene and one normal gene are called
carriers. Carriers typically do not exhibit any symptoms of the disorder but can pass the mutated gene to their offspring.
A 25% chance of inheriting two mutated genes and being affected by the disorder.
A 50% chance of inheriting one mutated gene and being a carrier, like their parents.
A 25% chance of inheriting two normal genes and not being affected or a carrier.
Cystic Fibrosis: Affects the lungs and digestive system, leading to severe respiratory and digestive problems.
Sickle Cell Anemia: A blood disorder that causes red blood cells to become misshaped, leading to various health complications.
Tay-Sachs Disease: A fatal genetic disorder that causes progressive damage to the nervous system.
Phenylketonuria (PKU): A metabolic disorder that can lead to intellectual disability if not treated.
Conclusion
Autosomal recessive inheritance is a significant mode of genetic transmission for various disorders. Understanding the mechanisms, risks, and options available for diagnosis, treatment, and family planning can help individuals and families make informed decisions. Advances in genetic testing and therapies continue to improve outcomes for those affected by autosomal recessive disorders.
