Facioscapulohumeral muscular dystrophy can be a cause of isolated childhood cognitive dysfunction.

Facioscapulohumeral muscular dystrophy is one of the most prevalent muscular dystrophies in the world, resulting from the deletion of tandem repeats on chromosome 4q35. Extramuscular associations include sensorineural hearing loss, mental retardation, and epilepsy. These manifestations are commonly found in those with large deletions and early onset of weakness. A 26-year-old patient with a long-standing history of hearing loss, learning disabilities, and epilepsy presented with new-onset weakness and an elevated serum creatinine kinase level. Genetic testing confirmed sporadic facioscapulohumeral muscular dystrophy with a fragment length of 12 kilobases (normal > 35 kilobases). This unique presentation suggests that facioscapulohumeral muscular dystrophy should be considered in the differential diagnosis of children with cognitive impairment, seizures, and hearing loss.