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Homocarnosinosis: Hypercarnosinuria
Author(s) -
Lunde Hilde,
Sjaastad Ottar,
Gjessing Leiv
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb10876.x
Subject(s) - anserine , carnosine , excretion , medicine , urine , endocrinology , paraplegia , urinary system , hereditary spastic paraplegia , chemistry , enzyme , biochemistry , spinal cord , psychiatry , phenotype , gene , histidine
Homocarnosine (γ‐aminobutyrylhistidine) is a brain‐specific dipeptide. Homocarnosinosis is a familial metabolic disorder in which spastic paraplegia, progressive mental deficiency, and retinal pigmentation coexist with increased CSF homocarnosine levels, i.e. approximately 20 times higher than the mean control level. In the present study, the urinary excretion of carnosine ( β ‐alanylhistidine) and anserine ( β ‐alanyl‐1‐methylhistidine) was determined in patients with homocarnosinosis and in their close relatives. Both the patients and their relatives were also loaded with chicken meat, which is rich in anserine and carnosine. The results were compared with those obtained in childhood hypercarnosinuria with serum carnosinase deficiency. Somewhat surprisingly, patients with homocarnosinosis were also shown to have hypercarnosinuria. Chicken meat loading in healthy individuals results in increased excretion of carnosine and anserine and, in addition, 1‐methylhistidine in the urine. Homocarnosinosis patients and patients with serum carnosinase deficiency also showed an increased excretion of carnosine and anserine, but 1‐methylhistidine was not detected in serum carnosinase deficiency, and it was present only in very small amounts in homocarnosinosis. This defect seems to be due to lack of the hydrolyzing enzyme activity. The biochemical and clinical similarities between adult homocarnosinosis and infantile serum carnosinase deficiency are intriguing. A complete insight into the relationship between them must await further investigation.