What type of inheritance pattern does Myotonic Dystrophy Type 1 exhibit?

Myotonic Dystrophy Type 1 (DM1) is inherited in an autosomal dominant manner, which means that only one copy of the mutated gene is sufficient to cause the disorder. This genetic condition results from a CTG triplet repeat expansion in the DMPK gene located on chromosome 19. Since the disorder is autosomal dominant, an affected individual has a 50% chance of passing the mutation to each offspring.

In families affected by DM1, the severity of the symptoms can vary widely, and it may also demonstrate a phenomenon called anticipation, where subsequent generations experience more severe symptoms or earlier onset of the disease due to the further expansion of the repeat. This unique inheritance pattern is crucial for genetic counseling, as it affects the risk assessment and management for family members of affected individuals.

The other inheritance patterns listed, such as X-linked recessive, autosomal recessive, and mitochondrial, do not apply to Myotonic Dystrophy Type 1, further supporting the fact that it follows the autosomal dominant pattern.