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Biotinidase deficiency: Factors responsible for the increased biotin requirement
Author(s) -
Baumgartner E. R.,
Suormala T.,
Wick H.,
Bausch J.,
Bonjour J. P.
Publication year - 1985
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/bf01800661
Subject(s) - biocytin , biotin , biotinidase deficiency , endocrinology , medicine , biotin deficiency , urine , chemistry , biochemistry , central nervous system
Inability to recycle biotin from endogenous biocytin in congenital biotinidase deficiency is associated with increased requirement of exogenous free biotin. We have observed that severe biotin depletion with clinical and biochemical consequences occurs within 12 days after birth in a newborn patient and within 15–20 days after withdrawal of biotin supplementation in four other patients. Our studies have shown that: Urinary loss of biotin and biocytin are major causes for this rapid biotin depletion. Intestinal absorption of biotin seems to be normal at least at the loading dose of 1.5 µg/kg. At normal or subnormal plasma biotin concentrations biocytin is found in low concentrations (below 1 nmoll −1 ) in plasma of patients but at much higher concentrations in urine (100–600 nmoll −1 ). An oral load of biocytin results in patients in unchanged biotin levels but in a marked rise of biocytin in plasma followed by rapid renal excretion of biocytin whereas in controls biotin levels in plasma increase rapidly and biocytin remains below detection levels.