| Histidinemia
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. | |