Distal Myopathies and Beyond: An Updated Overview of the Welander Distal Myopathy.

Myopathies are a heterogeneous group of disorders that primarily affect skeletal muscles and are classified as rare diseases owing to their low incidence. In particular, Welander distal myopathy is a rare, late-onset muscular disorder that was first described in 1951. Since then, substantial progress has been made in characterizing its clinical presentation and histopathological features. Despite these advances, many aspects of the disease, such as the underlying molecular mechanisms and factors driving phenotypic variability, remain unknown. Furthermore, the scarcity of reliable disease models not only limits the exploration of the molecular basis of the disease but also the development of effective treatments. In this review, we summarize the current knowledge of Welander distal myopathy and discuss potential directions in this field.