Verification of Hb O-Arab [beta 121(GH4)Glu-->Lys] by dual restriction enzyme analysis

First observation of homozygous hemoglobin hamadan (B 56 (D7) GLY-ARG) and beta thalassemia (-29 G>A)- hemoglobin Hamadan combination in a Turkish family

During screening surveys for beta thalassemia and abnormal hemoglobins in Mugla, a city located in the Aegean Region of Turkey, a hemoglobin variant was detected in two large families residing in two neigboring cities (i.e., Muğla and Aydin) without any clinical signs. Further analysis of the variant revealed it as Hb Hamadan (B 56 (D7) GLY-ARG). Family screening revealed the father of the propositus as homozygote Hb Hamadan. The grandfather of the index case was detected as combination of Hb Hamadan with beta thalassemia. The beta thalassemia carrier had a promotor mutation at -29 G>A, which is also a novel mutation. Furthermore, we described a simple and rapid restriction enzyme digestion protocol (Hha I) for the verification of Hb Hamadan. The clinical and hematologic data of the index case and his father showed that neither homozygous Hb Hamadan nor combination with beta thalassemia has clinical importance. This is also important especially from the prenatal diagnosis point of view.