scapuloperoneal

Scapuloperoneal refers to a pattern of hereditary muscle weakness that primarily involves the muscles stabilizing the shoulder blade (scapular stabilizers) and the muscles at the front of the lower legs (peroneal or dorsiflexor muscles). Conditions described by this pattern are typically referred to as scapuloperoneal muscular atrophy or scapuloperoneal syndrome. The disorder is rare and clinically heterogeneous, with onset usually in adolescence or early adulthood and a variable course.

Genetically, scapuloperoneal forms are characterized by genetic heterogeneity, with several autosomal dominant and autosomal recessive forms identified in different families. Mutations in multiple genes have been associated with scapuloperoneal weakness, and genetic testing can help establish a diagnosis in some cases. The underlying pathology may be myopathic (primarily muscle fiber disease) or neuropathic (nerve involvement), and some patients show features overlapping with distal hereditary motor neuropathies or other muscular dystrophies.

Common clinical features include prominent scapular winging due to weakness of the serratus anterior and related shoulder girdle muscles, foot drop or difficulty with ankle dorsiflexion, and varying degrees of proximal upper limb weakness. Reflexes and sensation are often preserved or only mildly affected, and facial muscles are typically less involved. Electromyography and nerve conduction studies help distinguish myopathic from neuropathic patterns, while muscle biopsy can show dystrophic or neurogenic changes.

Management is supportive and multidisciplinary, focusing on physical therapy to maintain strength and flexibility, orthotic devices for foot drop, and adaptive strategies. Genetic counseling is recommended given the hereditary nature. The prognosis is variable, with some individuals experiencing slow progression and others with more noticeable functional limitation over time.