[Alpha thalassemia/metal retardation syndrome--a new X-chromosome linked recessive genetically inherited symptom complex].

Two brothers are presented who were previously diagnosed to have atypical Smith-Lemli-Opitz syndrome. On repeated examinations, however, the facial anomalies of the patients suggested that they would have rather alpha-thalassaemia/mental retardation syndrome. The presence of hemoglobin H inclusions in the peripheral red blood cell supported the clinical suspicion. The search for hemoglobin H inclusions should be considered as a screening test when evaluating mentally retarded boys.