Histidinemia is a rare metabolic disorder characterized by elevated histidine levels in blood, urine, and cerebrospinal fluid, generally with no clinical repercussions. The disease is histidinemia (Monarch Disease Ontology term MONDO_0009345). Also known as: HIS deficiency, Hal deficiency, Histidinuria, histidase deficiency, histidine ammonia-lyase deficiency, histidinuria, hyperhistidinemia.