Genome-wide linkage screen for testicular germ cell tumour susceptibility loci

A family history of disease is a strong risk factor for testicular germ cell tumour (TGCT). In order to identify the location of putative TGCT susceptibility gene(s) we conducted a linkage search in 237 pedigrees with two or more cases of TGCT. One hundred and seventy-nine pedigrees were evaluated genome-wide with an average inter-marker distance of 10 cM. An additional 58 pedigrees were used to more intensively investigate several genomic regions of interest. Genetic linkage analysis was performed with the ALLEGRO software using two model-based parametric analyses and a non-parametric analysis. Six genomic regions on chromosomes 2p23, 3p12, 3q26, 12p13-q21, 18q21-q23 and Xq27 showed heterogeneity LOD (HLOD) scores of greater than 1, with a maximum HLOD of 1.94 at 3q26. Genome-wide simulation studies indicate that the observed number of HLOD peaks greater than one does not differ significantly from that expected by chance. A TGCT locus at Xq27 has been previously reported. Of the 237 pedigrees examined in this study, 66 were previously unstudied at Xq27, no evidence for linkage to this region was observed in this new pedigree set. Overall, the results indicate that no single major locus can account for the majority of the familial aggregation of TGCT, and suggests that multiple susceptibility loci with weak effects contribute to the diseas

The International Testicular Cancer Linkage Consortium:A clinicopathologic descriptive analysis of 461 familial malignant testicular germ cell tumor kindred

Objectives: Familial aggregation of testicular germ cell tumor (TGCT) has been reported, but it is unclear if familial TGCT represents a unique entity with distinct clinicopathologic characteristics. Here we describe a collection of familial TGCT cases from an international consortium, in an effort to elucidate any clinical characteristics that are specific to this population. Materials and methods: Families with >= 2 cases of TGCT enrolled at 18 of the sites participating in the International Testicular Cancer Linkage Consortium were included. We analyzed clinicopathologic characteristics of 985 cases from 461 families. Results: A majority (88.5%) of families had only 2 cases of TGCT. Men with seminoma (50% of cases) had an older mean age at diagnosis than nonseminoma cases (P = 0.001). Among individuals with a history of cryptorchidism. TGCT was more likely to occur in the ipsilateral testis (kappa = 0.65). Cousin pairs appeared to represent a unique group, with younger age at diagnosis and a higher prevalence of cryptorchidism than other families. Conclusions: Clinicopathologic characteristics in these familial TGCT cases were similar to those generally described for nonfamilial eases. However, we observed a unique presentation of familial TGCT among cousin pairs. Additional studies are needed to further explore this observation. Published by Elsevier Inc

Analysis of the DNDI gene in men with sporadic and familial testicular germ cell tumors

A base substitution in the mouse DndI gene resulting in a truncated Dnd protein has been shown to be responsible for germ cell loss and the development of testicular germ cell tumors (TGCT) in the 129 strain of mice. We investigated the human orthologue of this gene in 263 patients (165 with a family history of TGCT and 98 without) and found a rare heterozygous variant, p. Glu86Ala, in a single case. This variant was not present in control chromosomes (0/4,132). Analysis of the variant in an additional 842 index TGCT cases (269 with a family history of TGCT and 573 without) did not reveal any additional instances. The variant, p. Glu86Ala, is within a known functional domain of DNDI and is highly conserved through evolution. Although the variant may be a rare polymorphism, a change at such a highly conserved residue is characteristic of a disease-causing variant. Whether it is disease-causing or not, mutations in DNDI make, at most, a very small contribution to TGCT susceptibility in adults and adolescents. (c) 2007 Wiley-Liss, Inc

Genome-wide linkage screen for testicular germ cell tumour susceptibility loci.

A family history of disease is a strong risk factor for testicular germ cell tumour (TGCT). In order to identify the location of putative TGCT susceptibility gene(s) we conducted a linkage search in 237 pedigrees with two or more cases of TGCT. One hundred and seventy-nine pedigrees were evaluated genome-wide with an average inter-marker distance of 10 cM. An additional 58 pedigrees were used to more intensively investigate several genomic regions of interest. Genetic linkage analysis was performed with the ALLEGRO software using two model-based parametric analyses and a non-parametric analysis. Six genomic regions on chromosomes 2p23, 3p12, 3q26, 12p13-q21, 18q21-q23 and Xq27 showed heterogeneity LOD (HLOD) scores of greater than 1, with a maximum HLOD of 1.94 at 3q26. Genome-wide simulation studies indicate that the observed number of HLOD peaks greater than one does not differ significantly from that expected by chance. A TGCT locus at Xq27 has been previously reported. Of the 237 pedigrees examined in this study, 66 were previously unstudied at Xq27, no evidence for linkage to this region was observed in this new pedigree set. Overall, the results indicate that no single major locus can account for the majority of the familial aggregation of TGCT, and suggests that multiple susceptibility loci with weak effects contribute to the disease

Analysis of the DND1 gene in men with sporadic and familial testicular germ cell tumors.

A base substitution in the mouse Dnd1 gene resulting in a truncated Dnd protein has been shown to be responsible for germ cell loss and the development of testicular germ cell tumors (TGCT) in the 129 strain of mice. We investigated the human orthologue of this gene in 263 patients (165 with a family history of TGCT and 98 without) and found a rare heterozygous variant, p. Glu86Ala, in a single case. This variant was not present in control chromosomes (0/4,132). Analysis of the variant in an additional 842 index TGCT cases (269 with a family history of TGCT and 573 without) did not reveal any additional instances. The variant, p. Glu86Ala, is within a known functional domain of DND1 and is highly conserved through evolution. Although the variant may be a rare polymorphism, a change at such a highly conserved residue is characteristic of a disease-causing variant. Whether it is disease-causing or not, mutations in DND1 make, at most, a very small contribution to TGCT susceptibility in adults and adolescents