THE FIRST two cases of histidinemia were reported by Dr. Ghadimi in 1961.1 Only 10 to 15 additional cases have been detected since then and relatively few of these have been carefully investigated.2 The youngest patient with histidinemia is a male infant whose condition was diagnosed at 6 months of age,3,4 and the oldest known patient with histidinemia is a 13-year-old girl.5 Most of the other patients are less than 8 years old. Thus, there is no information on the clinical manifestations and biochemical findings of adults with histidinemia. Therefore, any generalizations made about histidinemia are based upon limited and incomplete understanding of the metabolic disorder.
Present Status of the Disease
Despite these reservations, it is pertinent to review the present status of the disease and to attempt to determine whether there are clinical features which are characteristic of histidinemia. Roughly half of the children with