Pellagra-Like Syndrome

Clinical Features

Freundlich et al. (1981) studied an Israeli-Arab family in which the parents were first cousins and 4 of 11 sibs had a pellagra-like rash with neurologic manifestations. They thoroughly studied 1 sib, a 14-year-old boy who had first been admitted at age 13 months with a red, scaly rash over the face, upper chest, hands, and legs. The rash disappeared with nicotinamide therapy. During childhood the pellagra-like skin rash recurred several times and was each time cured by nicotinamide. At age 14 years he showed, in addition to rash, confusion, diplopia, dysarthria, and ataxia. Again all clinical abnormalities cleared with nicotinamide. Laboratory findings excluded Hartnup disease: amino aciduria and indicanuria were absent, as was any evidence of tryptophan malabsorption. Tryptophan loading did not induce tryptophanuria and did not increase excretion of xanthurenic or kynurenic acids. The authors suggested that the affected sibs have a genetically determined block in tryptophan degradation.

Salih et al. (1985) likewise described a pellagra-like condition, which they interpreted as a 'new' hereditary defect of tryptophan metabolism, in a Sudanese family with consanguinity. The condition manifested itself as a pellagra-like skin rash within 8 weeks of birth, with signs of cerebellar ataxia and developmental retardation. Cataracts developed early. The authors stated in the abstract that none of 10 affected children had survived beyond 2 years of age; yet the illustrative case that they describe in detail died at the age of 31 months. In the pedigree illustrated, affected males and females occurred in 3 sibships of the highly consanguineous kindred. There appeared to be impairment in the synthesis of quinolinic acid and nicotinamide nucleotides from tryptophan. Hartnup disease (234500) is a disorder of tryptophan metabolism with pellagra-like light-sensitive rash and cerebellar ataxia.