A genetic epidemiological study of hereditary prostate cancer (HPC) in Finland: Frequent HPCX linkage in families with late-onset disease

Several predisposition loci for hereditary prostate cancer (HPC) have been suggested, including HPC1 at 1q24-q25 (OMIM #601518) and HPCX at Xq27-q28 ( OMIM #300147), Genetically homogeneous populations, such as that of Finland , and distinct subsets of families may help to minimize the genetic heterog eneity that complicates the genetic dissection of complex traits. Here, the role of the HPC1 and HPCX loci in a series of Finnish prostate cancer fami lies was studied, especially in subgroups of families defined by age, numbe r of affected cases, and the mode of disease transmission. DNA samples were collected from 57 Finnish HPC families with at least two living prostate c ancer patients. Linkage analysis was carried out with 39 microsatellite mar kers for the HPC1 region and 22 markers for the HPCX region. The maximum tw o-point LOD score for the HPCX was 2.05 (marker DXS1205, at 0 = 0.14), wher eas HPC1 LOD scores were all negative. In HOMOG3R analyses, significant evi dence of heterogeneity was observed. Subgroup analyses performed to explore the nature of this heterogeneity indicated that families with no male-to-m ale (NMM) transmission and a late age of diagnosis (>65 years) accounted fo r most of the HPCX-linked cases, The maximum HPCX LOD score in this subgrou p was 3.12 (0 = 0.001), Nonparametric sibling pair analyses gave a peak LOD score of 3.04 (P < 0.000093) for the NMM transmission subgroup, No subgrou p shelved any positivity for HPC1. This study suggests that the HPCX-linked prostate cancer families represent a distinct subgroup characterized by NM M transmission of disease and late age of diagnosis.