Long-Term Follow-Up of 58 Patients with Histidinemia Treated With a Histidine-Restricted Diet: No Effect of Therapy

¹ Department of Pediatrics, University of Vienna (Universitäts-Kinderklinik) Währinger Gürtel 18-20, A-1090 Vienna, Austria

Objective. There is no general agreement as to whether or not patients with histidinemia should be treated with a histidine-restricted diet because the majority of the patients are asymptomatic. Between April 1969 and December 1986 124 children with histidinemia were detected in the Austrian Neonates Screening Program and they received long-term follow-up.

Design. Fifty nine patients were treated with a histidine-restricted diet (35 mg/kg). The follow-up included determining biochemical parameters, physical examination and psychological assessment of 58 treated and 43 untreated patients. After termination of the Screening Program information about the patients' development was obtained through questionnaires and follow-up of 20 patients aged 11 to 17 years.

Results. Histidine blood levels decreased after institution of the diet, but rose again after termination of the diet. In the untreated patients histidine levels were highest at 1 year of age, decreasing with age. When the IQ scores of the treated and the untreated group were compared, significantly higher IQ scores were found in the 4-year-old and 6-year-old untreated patients (P < .05). Clinical symptoms were found in 27 patients; treated and untreated patients were equally affected. The clinical observations included speech defects, psychomotor and general retardation, emotional disturbances, recurrent respiratory infections, and miscellaneous symptoms such as atopic dermatitis.

Conclusion. We conclude that patients with histidinemia do not benefit from dietary treatment.