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a hereditary aminoacidopathy marked by excessive histidine in the blood and urine due to deficient histidase activity; many affected persons show mild mental retardation and disordered speech development.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
A metabolic disorder characterized by speech defects, growth deficiency, and mild mental retardation in some patients; associated with elevation of blood histidine level and excretion of histidine and related imidazole metabolites in urine due to deficiency of histidine ammonia lyase or histidinase; autosomal recessive inheritance, caused by mutation in the histidinase gene (HIS) on chromosome 12q.
[histidine + G. haima, blood, + -ia]
Farlex Partner Medical Dictionary © Farlex 2012
histidinemiaMolecular medicine A common–1:10,000–often asymptomatic AR condition characterized by a deficiency of histidase, the enzyme that converts histidine to urocanic acid in the liver and skin Clinical Variable which, when symptomatic, is of neonatal onset with impaired speech, growth and mental retardation Lab Some excess histidine is transaminated to imidazole, the urinary metabolite of which, imidazolepyruvic acid, is detectable by the ferric chloride test or by Phenistix, otherwise used to diagnose PKU
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.