Familial Hodgkin's lymphoma in Scandinavia.

From 2005 to 2010, eight families with clustering of Hodgkin's lymphoma and other lymphoproliferative disorders were found: Hodgkin's lymphoma 9 cases, chronic lymphocytic leukemia 8, non-Hodgkin's lymphoma 3, and multiple myeloma 1 case. Seven cases of Hodgkin's lymphoma, all males, were seen in pleiotropic pairs of affected family members from two successive generations; two patients were sisters. Five of the seven pairs showed sign of anticipation. The 7 males with Hodgkin's lymphoma were found in 5 patrilineal pairs and 2 matrilineal pairs; 6 parent-offspring pairs and 1 uncle-nephew pair. In contrast to the matrilineal pairs, all patrilineal pairs, apart from one family with an only child, had healthy older siblings in accordance with a birth-order effect. The association among Hodgkin's lymphoma, males, and other lymphoproliferative disorders undoubtedly reflects genotypic traits of the susceptibility. A non-Mendelian segregation is discussed comprising genomic parental imprinting and incomplete penetrance susceptibility in both familial and solitary cases.