A case of the morning glory disc anomaly is reported in which alternating contraction and dilation movements were observed and documented with fundus photographs. The movements are attributed to an anomalous communication between the subretinal and subarachnoid spaces that permits flux of fluid to occur between the two compartments, with consequent variation in the degree of retinal elevation within the excavated portion of the lesion. The clinical features of the morning glory disc anomaly, peripapillary staphyloma and optic disc coloboma are presented, and the relationship among these lesions is discussed. The author concludes that the morning glory disc anomaly is a clinical entity distinct from peripapillary staphyloma and optic disc coloboma. It is thought to be due to dysgenesis of the distal optic stalk leading to anomalous persistence of the extension of the cavity of the optic cup into the stalk.

A novel point mutation in the ND6 subunit of complex I at position 14,459 of the mitochondrial DNA (MTND6*LDY T14459A) was identified as a candidate mutation for the highly tissue-specific disease. Leber's hereditary optic neuropathy plus dystonia. Since the MTND6*LDYT14459A mutation was identified in a single family, other pedigrees with the mutation are needed to confirm its association with the disease. Clinical, biochemical, and genetic characterization is reported in two additional pedigrees. Leber's hereditary optic neuropathy developed in two family members in one pedigree. The daughter had clinically silent basal ganglia lesions. In a second pedigree, a single individual presented with childhood-onset generalized dystonia and bilateral basal ganglia lesions. Patient groups that included individuals with Leigh's disease, dystonia plus complex neurodegeneration, and Leber's hereditary optic neuropathy did not harbor the MTND6*LDYT14459A mutation, suggesting that this mutation displays a high degree of tissue specificity, thus producing a narrow phenotypic range. These results confirm the association of the MTND6*LDYT14459A mutation with Leber's hereditary optic neuropathy and/or dystonia. As the first genetic abnormality that has been identified to cause generalized dystonia, this mutation suggests that nuclear DNA or mitochondrial DNA mutations in oxidative phosphorylation genes are important considerations in the pathogenesis of dystonia.

Periodic vestibulocerebellar ataxia is genetically distinct from those autosomal dominant ataxias for which chromosomal localization has been established.

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