What is the inheritance pattern of MUTYH Associated Polyposis?

MUTYH Associated Polyposis (MAP) is characterized by an autosomal recessive inheritance pattern. This means that an individual must inherit two copies of the mutated gene (one from each parent) to express the condition. Parents of an affected individual are typically carriers of one mutation each; they may not exhibit any symptoms of the disorder themselves but can pass the mutated gene to their offspring.

In the case of MAP, the mutations occur in the MUTYH gene, which plays a crucial role in the DNA repair process. When both copies of this gene are mutated, it leads to a failure in repairing DNA damage, increasing the likelihood of developing multiple colorectal polyps and potentially colorectal cancer.

This inheritance pattern fundamentally distinguishes it from autosomal dominant conditions, where only one mutated copy of the gene is sufficient for the manifestation of disease. Similarly, the condition is not linked to X-linked inheritance, where the trait is passed down through the X chromosome, nor does it relate to mitochondrial DNA inheritance, which involves genes passed from mother to offspring through mitochondria. Understanding these inheritance mechanisms is essential for genetic counseling and risk assessment in families affected by MAP.