Hereditary motor and sensory neuropathy with spastic paraplegia and optic atrophy: report on a family

We describe two siblings affected by a motor and sensory neuropathy starting in childhood. Already in infancy, a spastic gait disturbance had become obvious, leading later to multiple surgical interventions. In adolescence, progressive loss of vision developed. At the time of our examination, both siblings showed severe weakness and atrophy of the distal muscles of legs and arms. Tendon jerks were brisk in proximal muscles; in the lower extremities, muscle tone was increased. Visual acuity was severely decreased. Nerve conduction studies revealed an axonal degeneration. This finding was confirmed by evaluation of a sural biopsy specimen in one patient, showing only few remaining myelinated fibres without signs of demyelination. This combination of hereditary motor and sensory neuropathy with spastic paraplegia and optic atrophy shows features of both hereditary motor and sensory neuropathy V and VI according to the classification of Dyck, indicating that these subtypes may not represent distinct entities.