The Ala35Thr mutation can be confirmed by restriction analysis. Lanes 1 and 5: control. Lanes 2 and 6: the patient's mother. Lanes 3 and 7: the patient's father. Lanes 4 and 8: the patient. Restriction analysis with HAEIII and BstEII, on DNA extracted from blood, confirms heterozygosity for the Ala35Thr mutation in both parents and homozygosity in the patient.