[Two siblings of distal hereditary motor neuropathy with choroideremia]

Two brothers, 31 and 25 years of age, with distal hereditary motor neuropathy (distal HMN) and choroideremia are reported. Their parents were second cousins. During the first decade, their visual acuity gradually diminished with night blindness, accompanied by weakness of the legs. From the third decade, they noticed weakness of the hands. The neurological signs of both cases could be summarized as follows: bilateral pes cavus, Charcot-Marie-Tooth type distal atrophy and weakness of the four limbs, no sensory deficit, hyperreflexia in the upper limbs and knees, absent ankle jerks and plantar reflexes, and severe visual impairment due to choroideremia. In addition to these signs, the younger patient showed nystagmus and limb kinetic ataxia suggesting cerebellar involvement. Muscle biopsies and EMG studies revealed chronic neurogenic changes. MCV's in the median nerves were normal, but the extensor digitorum brevis muscles were totally denervated. SCV's, the amplitude of sensory action potentials and sural nerve biopsies were normal. In both patients, elevated CSF protein without pleocytosis and high level of serum IgA & E were demonstrated. Associations of choroideremia and abnormal laboratory findings as noted in our cases have not been so far reported in distal HMN, but we suppose these disorders may be genetically related.