An autosomal recessive cerebellar ataxia syndrome with upward gaze palsy, neuropathy, and seizures.

The authors describe three siblings born to consanguineous parents with early onset ataxia, dysarthria, myoclonic, generalized tonic clonic seizures, upward gaze palsy, extensor plantar reflexes, sensory neuropathy, and normal cognition. Direct screening excluded mutations in FRDA, TDP1,and SACS genes and at 8344, 3243, and 8993 positions of mitochondrial DNA. Linkage analysis excluded AOA-1, EPM1, EPM2A, EPM2B, CAMOS, and recessive ataxias linked to chromosome 9q34-9qter.

G(M2)-ganglioside metabolism in situ in mucolipidosis IV fibroblasts.

Mucolipidosis IV (ML IV) is an inherited lysosomal disorder for which the primary biochemical defect has not been identified. In order to detect any defect in glycosphingolipid metabolism, we have examined the metabolism of sphingosine-labeled (3H)G(M2) in situ in fibroblasts from patients diagnosed with ML IV. Fibroblasts were exposed for 10 days in medium containing (3H)G(M2) (15 uM; Sp.

Late-onset GM2 gangliosidosis: Ashkenazi Jewish family with an exon 5 mutation (Tyr180-->His) in the Hex A alpha-chain gene.

Late-onset GM2 gangliosidosis is a variant form of Tay-Sachs disease characterized by onset of symptoms and signs in adolescence or in early adult life. The deficiency of beta-hexosaminidase A (Hex A) in this form of GM2 gangliosidosis has been invariably associated with the presence of the Gly269-->Ser substitution in the alpha-chain. We found two siblings of Ashkenazi Jewish descent diagnosed with late-onset GM2 gangliosidosis who were negative for the Gly269-->Ser mutation.

Mitochondrial encephalomyopathies presenting with features of autonomic and visceral dysfunction.

Three children are reported with mitochondrial encephalomyopathy who presented with autonomic dysfunction. Autonomic dysfunction included gastrointestinal dysmotility, apnea, cardiac arrhythmias, decreased lacrimation, supersensitivity to metacholine, altered sweating, and postural hypotension. These patients illustrate that in some mitochondrial encephalomyopathies autonomic features may be prominent and can mimic the clinical features associated with hereditary sensory and autonomic neuropathies.

The application of laser microprobe mass analysis to the study of biological material.

Laser microprobe mass analysis (LAMMA) is an investigational method which is a powerful tool for the identification and quantitation of various elements present in small volumes of tissue. LAMMA is highly sensitive and capable of rapidly detecting concentrations of 1-3 p.p.