[Chronic hexosaminidase A deficiency associated with pure sensory peripheral neuropathy]. / Deficiencia crónica de hexosaminidasa A asociada a neuropatía periférica sensitiva pura.

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.

Deficiencia crónica de hexosaminidasa A asociada a neuropatía periférica sensitiva pura. / [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.

Deficiencia crónica de hexosaminidasa A asociada a neuropatía periférica sensitiva pura. / [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.

Familial congenital facial diplegia: electrophysiologic and genetic studies.

A 13-year-old boy with autosomal-dominant congenital facial diplegia was evaluated by electrophysiologic and genetic investigations. Thirteen members of his family were affected over 4 generations. The electrophysiologic studies revealed blink reflex abnormalities. Both R1 and R2 responses were prolonged on the left side after ipsilateral stimulation, while R2 was also delayed by contralateral stimulation. Ipsilateral R1 and R2 were of normal latencies when the right side was stimulated. A third ipsilateral response at 63 msec of latency could be obtained when stimulating the left side. These findings suggest functional damage to the brainstem. Further support for this interpretation was provided by the prolonged time between waves I and V, bilaterally, documented by study of brainstem auditory evoked potentials.

Tools to differentiate immunologic and non-immunologic myasthenia gravis in infancy.

Twelve patients between 15 months and 13 years of age with clinical and pharmacological features of myasthenia gravis were studied. Repetitive nerve stimulation did not offer valuable information; the patients demonstrated either inspecific muscular decremental response or had normal behavior. Two clear groups of patients were identified after measurements of acetylcholine receptor (AChR) antibodies and MEPP amplitude recorded in the diaphragm of mice injected with sera from those patients. The first group included patients with positive AChR antibodies titers and decreased MEPP amplitude. The second one had negative AChR antibodies titers and MEPPs with normal amplitude. These data strongly suggest immunologic and non-immunologic mechanisms for the former and later respectively.