Malmö International Brother Study (MIBS): an international survey of brother pairs with haemophilia.

Malmö International Brother Study (MIBS) was initiated in 1996 in order to set up an international registry of twins and non-twin brothers with haemophilia and to search for genetic and compound factors predisposing for inhibitor development. As of July, 1997, 178 brother pairs are registered (143 haemophilia A and 35 haemophilia B patients). Sixteen of these pairs are twins. In 48 of the brother pairs (27%) there is a history of inhibitors, in 25 of them involving only one of the brothers. Immune tolerance induction has been attempted in 13 brother pairs (27%) and in four pairs the inhibitor has been eradicated. Additional demographic data need to be collected and, if possible plasma, IgG and DNA samples will be taken from inhibitor patients to serve as a tool for basic inhibitor experiments.