A double heterozygote for (deltabeta)0-thalassemia and codons 41/42 (-TTCT) behaves as a homozygote for the frameshift mutation in a Chinese family.

We present the case of a child in whom beta-thalassemia (thal) major was apparently caused by homozygosity for a 4-base deletion mutation [codons 41/42 (-TTCT)] of the beta-globin gene. However, the mutation was not identified in the father. The presence of a deletional beta-thal was detected by long-range polymerase chain reaction (PCR). We emphasize that the mutations found in the patient should always be confirmed to be present in both parents before molecular analysis is employed for clinical purposes.