Clinical description of a homozygous Lys 1169* variant in the DYSF gene associated with autosomal recessive Miyoshi muscular dystrophy type 1: A familial case report

Miyoshi Muscular Dystrophy Type 1 is a rare autosomal recessive myopathy caused by mutations in the dysferlin (DYSF) gene. This disease presents with progressive distal lower limb weakness, such as gastrocnemius and soleus muscles resulting in difficulty standing on tiptoes, walking, and climbing stairs. We describe a family consisting of 6 siblings, 2 affected males, 1 affected female, 1 affected-death female, and 2 unaffected females. The affected members of this family have lived without an appropriate diagnosis for more than 20 years. Our patients have a homozygous nonsense pathogenic variant of the DYSF gene with 0 frequency in the Genome Aggregation Database. Our study shows that genetic testing provides a crucial aid to doctors when the physical examination and the clinical history are insufficient. It also emphasizes that a precise and accurate diagnosis prompts the correct management of a complex case.