Multiple sclerosis and latitude: a new perspective on an old association.

For 68 years latitude has been identified as an important risk factor in the occurrence of multiple sclerosis (MS), but not satisfactory explanation has been offered for this relationship. Epidemiological studies of MS, however, have failed to take into account the degree of change in the amount of ambient light over the course of the year, a variable which is closely related to photoperiod and latitude. Seasonal affective disorder (SAD), another illness for which latitude is a risk factor, appears to be related to the decrease in ambient light during the winter months, and offers some relevant insights into the geographical distribution of risk for developing MS. Researchers have found a relationship between degree of reported seasonal difficulties in a population sample and altered immunological function. Furthermore, the effects of bright light on mood have been shown to be regulated through the eye. We hypothesize that the risk of developing MS is related to impairment of the immune system caused by light deprivation prior to adulthood.

Arthrogryposis multiplex congenita occurring with maternal multiple sclerosis.

All children of a mother with multiple sclerosis (MS) had increasing grades of congenital joint contractures without demonstrable neuromuscular disease. Two had talipes equinovarus, one had congenital hip subluxation, and the youngest had arthrogryposis multiplex congenita. Maternal MS may be causally related to the development of congenital joint contractures.

Familial intermittent ataxia with possible X-linked recessive inheritance. Two patients with abnormal pyruvate metabolism and a response to acetazolamide.

Five males in one kindred suffered from intermittent ataxia and one female may have been more mildly affected. The pattern of inheritance strongly suggests X-linkage. Cerebral pathology in one case had some features of Leigh's disease. A defect in pyruvate metabolism was found in two cases. Acetazolamide gave a temporary clinical and biochemical improvement in two cases.

Machado-Joseph disease in an American-Italian family.

An American-Italian family is described as affected by an autosomal dominant inherited ataxia which meets the clinical diagnostic criteria for Machado-Joseph disease. This disorder no longer appears to be limited to individuals of known Portuguese ancestry.

Hereditary spastic paraplegia: a clinical and genetic study of cases in the north-east of England.

Patients in the north-east of England with hereditary spastic paraplegia and their immediate families were examined clinically and studied for evidence of linkage or association with polymorphic genetic systems. There were no observable clinical differences between patients with and without a positive family history. Family histories were compatible with autosomal dominant transmission, there was no evidence of linkage with any system, but there was a significant association with HLA-A1.

Choline chloride in the treatment of cerebellar and spinocerebellar ataxia.

The use of orally administered choline chloride in the treatment of cerebellar and spinocerebellar ataxia was investigated by a short-term double-blind crossover trial in 20 patients with ataxia. These patients, who include 7 with Friedreich's ataxia, 7 with mixed spinocerebellar ataxia and 6 will primary cerebellar degeneration received placebo and 6g/day or 12g/day of choline with crossover at 6 weeks. Serum choline levels were measured 1 h after the first daily dose. Mild but significant improvement in upper limb co-ordination was noted in 3 patients with Friedreich's ataxia, 3 with mixed ataxia and 4 patients with primary cerebellar degeneration. Improvement in gait and lower limb co-ordination was observed in only 2 patients (one with cerebellar ataxia and 1 with mixed ataxia) There was no correlation between serum choline levels and clinical response to choline. Choline chloride produces a mild but functionally significant improvement in motor co-ordination in some patients with cerebellar and spinocerebellar ataxia.

Pattern visual evoked responses in hereditary spastic paraplegia.

Pattern visual evoked responses were studied in 13 patients from nine families with dominant herditary spastic paraplegia and in seven sporadic cases. The responses were normal in all the dominantly inherited cases but abnormal in three of the seven sporadic cases.

Visual involvement in Friedreich's ataxia and hereditary spastic ataxia. A clinical and visual evoked response study.

Visual involvement was assessed in 21 patients with Friedreich's ataxia and in 17 patients with spastic ataxia by neuro-ophthalmic examination and by recording visual evoked responses (VERs). Two thirds of the patients with Friedreich's ataxia had some degree of visual impairment and an abnormal VER, whereas only three of the 17 patients with spastic ataxia showed abnormalities. The patients with Friedreich's ataxia could be subdivided into two groups, one with and the other without visual involvement; there was no correlation between the presence and severity of visual involvement and age or duration of symptoms in the group as a whole. Patients with the most severe degrees of visual impairment usually had flat VERs, whereas in less severely affected cases, the responses were reduced in amplitude, were delayed, and showed an increased degree of temporal dispersion. The findings have pathophysiological implications and raise the question of heterogeneity in Friedreich's ataxia.

Leber's optic neuropathy: clinical and visual evoked response studies in asymptomatic and symptomatic members of a 4-generation family.

A clinical and neuro-ophthalmological examination using tests of visual acuity, quantitative visual field analysis, tests of colour discrimination, ophthalmoscopy, and pattern visual evoked responses was performed on 2 symptomatic and 16 asymptomatic members of a family with Leber's optic neuropathy. The visual evoked responses were abnormal in the 2 clinically affected males and in 1 asymptomatic male. Tests of colour discrimination with Ishihara plates, the Farnsworth-Munsell 100 hue test, and the Nagel anomaloscope revealed abnormalities in 8 asymptomatic family members, with the Farnsworth-Munsell test proving to be the most sensitive to mild abnormalities of colour discrimination. The occurrence of detectable neuro-ophthalmological abnormalities within this family is in keeping with the expected pattern of transmission of Leber's optic neuropathy. The significance of detection of presymptomatically affected cases and asymptomatic carriers is discussed.

An investigation of pyruvate metabolism in patients with cerebellar and spinocerebellar degeneration.

This study extends previous observations of pyruvate metabolism in the spino-cerebellar degenerations by screening for abnormalities of pyruvate oxidation using the rise in blood pyruvate after an oral glucose load and examining the activity of the lipoamide dehydrogenase (LAD) moeity of the pyruvate dehydrogenase complex in the serum of 31 patients with Friedreich's ataxia, hereditary spastic ataxia and primary cerebellar degeneration. Serum LAD activity was significantly reduced in 10 Friedreich's ataxia patients when compared to controls and to 10 patients with spastic ataxia, thus confirming previous studies. Two patients with Friedreich's ataxia and 2 with primary cerebellar degeneration had abnormal blood pyruvate curves after oral glucose loading. The findings suggest that abnormal pyruvate oxidation occurs in some cases of Friedreich's ataxia and primary cerebellar degeneration and that the abnormality of pyruvate metabolism is not necessarily reflected in the serum LAD activity of these patients. The relevance of these findings to the heterogeneity of the hereditary ataxias is discussed.

The effect of luteinizing hormone releasing hormone (LRH) on pituitary gonadotropins in male homosexuals.

Basal serum LH and FSH values were found to be within normal limits in 9 homosexual men. The mean LH and FSH responses following the intravenous administration of 100 microgram of LRH were not significantly different from that of heterosexual controls. In addition, the mean basal plasma serum testosterone was similar in the two groups. There is thus no definite implication of endocrine factors in the genesis of male homosexuality.