Faculty Bibliography

We studied 33 affected members in a family with autosomal dominant 'pure' familial spastic paraplegia (FSP). Symptoms began in the fourth or fifth decade, expression varied, and progression was slow. We excluded close linkage to the HLA locus (distal end of short arm of chromosome 6); C8 alpha-gamma locus (proximal end of short arm of chromosome 1); PGM1 (middle region of short arm of chromosome 1); and P blood group (location unknown). Although there was no statistically significant linkage between FSP and any of the other markers, lod scores were positive with loci for GC (vitamin D binding globulin) located on chromosome 4 (4q11-q13) and Rh located on chromosome 1 (1p34-p36)

Confluent cultures of human skin fibroblasts were maintained for 10 days with sphingosine labeled [3H]GM2. Labeled medium was then replaced with normal medium and the cells maintained for 42 days with weekly medium changes. Cells were harvested at regular intervals and cells, medium, and trypsin digest supernatant analyzed for [3H]GM2 and its metabolic products. The ganglioside can be membrane associated and removed by trypsin, or membrane incorporated and trypsin insensitive. The membrane incorporated material is apparently transported to the lysosomes slowly by membrane flow, where 80% of the cellular GM2 can be metabolized by day 42. [3H]GM2 as well as its metabolic products in control cells is continuously released into the medium, during which it can also become associated with the cell surface membrane. There is no detectable metabolism of the [3H]GM2 in GM2 gangliosidosis cell lines over the extended post-labeling period, indicating that there is no residual enzyme activity in these cells. Undegraded GM2 is continuously released into the medium and remains associated with the cell surface membrane as well

Macular halos describe a striking clinical finding of bilaterally elevated, doughnut-shaped, white rings around th fovea. This paper presents the third well-documented report of the association of macular halos with Niemann-Pick type B disease, demonstrated by color photographs and subtle fluorescein angiographic findings. The systemic association with Niemann-Pick type B disease was confirmed by bone marrow biopsy and enzyme assay. Of 13 family members examined, only the proposita had macular halos; 10 were found to be carriers by sphingomyelinase assay. Recognition of this pathognomonic eye finding warrants more widespread awareness as a presenting sign of Niemann-Pick type B disease

A 24-week fetus with GM1 gangliosidosis (type 1) was studied using biochemical and histopathologic methods. Foam cells in viscera and placenta demonstrated widespread accumulation of a lipidlike material. By microscopy, central nervous system storage appeared confined to the retina and dorsal root ganglia, but the brain ganglioside content was measurably elevated compared with that of age-matched controls. These data, along with those of others, imply that, if the observed pathologic findings are irreversible, any attempts at intrauterine therapy must commence prior to the middle of the second trimester

We report 2 brothers with progressive ataxia, seizures, myoclonus, supranuclear ophthalmoplegia, progressive visual loss and embolic strokes. The epilepsy and myoclonus came on many years after the onset of the ataxia. In the more severely affected brother the myoclonus was often unilateral and focal but ultimately involved both sides of the body. His sibling had only unilateral myoclonus after a contralateral middle cerebral artery stroke. When focal, persistent and unilateral, the myoclonus in both brothers was clinically similar to epilepsia partialis continua except that muscles of the trunk and proximal limbs were the most affected. It was exacerbated by movement of the affected part but was otherwise not stimulus sensitive. The more severely affected brother had a pigmentary retinopathy and a cardiac fibromyxoid valvulopathy. In his sibling, visual loss was not fully investigated and the heart was not examined at autopsy though he had a longstanding heart murmur. Neuropathological studies showed pancerebellar cortical atrophy, cell loss in the inferior olivary nuclei and old right middle cerebral artery infarctions in both brothers. Biochemical assays for known metabolic diseases were negative. We suggest that this syndrome represents a unique autosomal recessive form of progressive myoclonus epilepsy of unclear aetiology. It is distinguished from other familial myoclonus epilepsies by the presence of early onset cerebellar ataxia, supranuclear ophthalmoplegia, pigmentary retinopathy and possibly cardiac valvulopathy with subsequent cerebral emboli