© Kamla-Raj 2003                                                                         Int J Hum Genet, 3(4): 247-250 (2003)

Contribution of Genetic Factors in Variation of Clinical Severity

Among Siblings with Homozygous b-Thalassemia in

Two Indian Families

Anita Nadkarni,  A. Gorakshakar,  K. Ghosh,  Roshan Colah and  D. Mohanty

Institute of Immunohaematology (ICMR), 13th Floor, New Multistoreyed Building,

KEM Hospital Campus, Parel, Mumbai  400 012, Maharashtra, India

Keywords b thalassemia; clinical diversity; India

Abstract We  report two Indian  families with a  variable degree  of anemia in  two b thalassemia homozygous siblings from each family. In both the families the siblings with delayed presentation had co-inherited an a thalassemia 2 determinant as well as a gene for increased Hb F production. As against this, the severely affected siblings from both the families had shown either absence or presence of only one ameliorating factor. It appears that contribution of two ameliorating factors (a thalassemia 2, Xmn 1 polymorphism) could synergistically compensate for lack of b-globin chains in the homozygotes leading to a milder presentation in the form of thalassemia intermedia.

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