Haematological and genetic features of deltabeta-thalassaemia in Pakistan

ABSTRACT

To describe the haematological and genetic features of db-thalassaemia in Pakistani patients. Descriptive case series. Department of Pathology, PNS Shifa, Karachi and Department of Haematology, Armed Forces Institute of Pathology, Rawalpindi, from January 1994 to April 2004. Thirteen individuals from six unrelated Pakistani families with a haematological diagnosis of dbthalassaemia were studied. A brief clinical history, and the results of blood counts, absolute values, Hb-F, Hb-A2, and haemoglobin electrophoresis were recorded. The DNA from each subject was first screened for the b-thalassaemia mutations found in the Pakistani population. The samples were then screened for the Inv/Del Gg[Agdb]o. The subjects included six heterozygotes, six homozygotes and one compound heterozygote of db- and b-thalassemia. All heterozygotes and 4/6 homozygotes were asymptomatic. One homozygote had thalassemia intermedia while another had transfusion dependent anaemia. The mean Hb, TRBC, MCV, MCH, Hb-F and Hb-A2 in db-thalassaemia heterozygotes were 11.6 g/dl, 5.37 x 1012/L, 70.9 fl, and 21.7 pg, 14% and 2.6% respectively. The same values in the four untransfused homozygotes were 10.6 g/dl, 5.34x1012/L, 69.2fl, and 20.8pg, 100% and 0% respectively. The mutation analysis revealed that all 13 individuals had the same Inv/Del Gg[Agdb]o. db-thalassaemia is a rare disorder in Pakistan. Although the clinical picture is very mild its combination with b-thalassaemia trait can produce a sever transfusion dependent thalassaemia. The DNA based diagnosis is possible in the prenatal as well as the postnatal period