Chronic hexosaminidase A deficiency associated with pure sensory peripheral neuropathy

One patient with hexosaminidase A (Hx A) deficiency, which produces GM2 gangliosidosis, developed a complex progressive neurological syndrome, starting when he was 10 years old, which encompassed intellectual impairment, cerebellar involvement, features of upper and lower motoneurones compromise and sensory neuropathy without signs of motor fibre damage within the peripheral nerves. Sural nerve biopsy demonstrated loss of myelinated fibres, mainly of those of large and small diameters, clusters of small diameter fibres, fibres with abnormal thin myelin sheaths related to their axonal diameters, axonal degeneration, segmental and paranodal demyelination and remyelination. Electronmicroscopic examination showed small electrondense, non specific, bodies and concentric lamellar inclusions within the cytoplasm of the Schwann cells. These findings demonstrate that pure sensory peripheral neuropathy should be considered as part of the spectrum which may result from Hx A deficiency.