MULTIPLE-MYELOMA IN 3 SIBLINGS

There have been 53 reported instances of myeloma occurring in more tha n one family member but in only three of these reports have three sibl ings been affected (Alexander & Benninghoff 1967: Maldonado & Kyle 197 4; Horwitz et al. 1985; Crozes-Bony el al. 1995). We report a family w here three siblings had an unequivocal diagnosis of myeloma made over a period of six years. The paraprotein isotype was IgG kappa in two of the siblings and kappa light chain only in the remaining sibling. The importance of these cases lies in the fact that they are highly sugge stive of a genetic predisposition to the development of myeloma. Becau se of the high prevalence of p53 abnormalities in certain types of fam ilial cancer screening for p53 mutation in exons 5-8 was performed by denaturing gradient gel electrophoresis (DGGE) on DNA extracted from t he bone marrow of the three siblings, Although a p53 mutation was iden tified in one of the siblings it was felt to represent a somatic as op posed to a germline mutation.