Histidinemia

Histidinemia is an inherited condition characterized by elevated levels of histidine in blood, urine, and the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). Histidine is an amino acid that acts as a building block for many different proteins. 

In most cases, histidinemia does not cause health problems. Most people with elevated histidine levels are unaware that they have this condition. Rarely, people with histidinemia have intellectual disabilities, learning disabilities, or behavioral problems. Having a medical complication during or soon after birth might increase the risk of developmental problems in people with histidinemia. 

Other names

HAL deficiency; HIS deficiency; Histidase deficiency; Histidine ammonia-lyase deficiency; Histidinuria; Hyperhistidinemia

Inheritance pattern

Autosomal recessive

Related genes

HAL

Source: MedlinePlus Genetics, U.S. National Library of Medicine.