Analysis of mitochondrial DNA in Leber's hereditary optic neuropathy.

Twenty-eight patients from 25 maternal lineages with Leber's hereditary optic neuropathy (LHON) were investigated by restriction enzyme analysis for the presence or absence of the point mutation described by Wallace et al. The mutation was identified in 18 of 25 (72%) families with LHON. This provides further evidence that this mutation is present in the majority of patients with LHON. In 19 of these families with LHON, additional analysis using sequencing, oligonucleotide probing, and competitive oligonucleotide priming of PCR products was performed. In 14 cases with the site loss the point mutation was present, and five without the site loss had the wild type sequence in this region.

Vitamin A deficiency in Crohn's disease.

Fifty two patients with Crohn's disease (31 outpatients and 21 inpatients) were investigated for evidence of vitamin A deficiency. Eleven (21%) had low plasma retinol concentrations (less than 1.2 mumol/l (34.3 micrograms %)). Five of these were outpatients and plasma retinol was only slightly reduced (greater than 1.0 mumol/l (28.6%)). All outpatients weighed 80% or more of ideal, and were considered at low risk of developing vitamin A deficiency. In contrast, of the six inpatients with low plasma retinol concentration, five had a level of less than 1.0 mumol/l (28.6 micrograms %) and weighed less than 80% ideal. Three of these had impaired dark adaptation and a plasma retinol concentration of less than 0.8 mumol/l (less than 22.9 micrograms %). As a group, the inpatients were more protein depleted than the outpatients, with respect to serum albumin (p less than 0.01), transferrin (p less than 0.001), and prealbumin (p less than 0.001) but retinol binding protein levels were not significantly lower. It is suggested that patients with extensive small bowel Crohn's disease, who weigh less than 80% of ideal weight, merit measurement of plasma retinol concentration. Those with plasma retinol less than 0.8 mumol/l (less than 22.9 micrograms %) run a high risk of night blindness. Vitamin supplements should be given and protein depletion corrected.

Clinical and biochemical findings in Leber's hereditary optic atrophy.

Clinical findings in Leber's hereditary optic atrophy (LHOA) are reviewed and the results given of treatment with a regimen based on the hypothesis that the disease is a manifestation of cyanide toxicity. Recent biochemical investigations confirm disturbed cyanide metabolism and suggest that zinc deficiency may be implicated.