Phenotypic Variation in Dysferlinopathy

Mutations in the dysferlin gene cause distinct phenotypes of muscular dystrophy known by the term “dysferlinopathy”. Nowadays, four subtypes of dysferlinopathies have been established: limb-girdle muscular dystrophy 2B (LGMD 2B), Miyoshi myopathy (MM), distal anterior compartment type and scapuloperoneal type.We report a girl with dysferlinopathy with an unusual involvement of muscles in lower extremities and her brother whose symptoms started after the diagnosis of his sister.Both of them had lower limb weakness, marked elevation of serum creatine kinase (CK) levels and myopathic patterns in electromyography (EMG). Muscle biopsy of the girl who was diagnosed as having dysferlinopathy disclosed dystrophic changes and an absence of dysferlin. She had both proximal and distal weakness of the lower limbs presented in a 5-year-period. However her brother had difficulty only in foot dorsiflexion at the beginning of the symptoms.In conclusion, phenotypic variability, particularly at onset is one of the features of dysferlinopathies. To recognize and distinguish them from polymyositis is important to protect the patients from unnecessary treatment modalities. Recent imaging studies indicate that the pattern of muscular involvement is essentially uniform when both symptomatic and presymptomatic involvement is considered.