Project description:The main genetic factors for familial melanoma remain unknown in more than 75% of families. CDKN2A is mutated in around 20% of melanoma-prone families. Other high-risk melanoma susceptibility genes explain less than 3% of families studied to date. We performed the first genome-wide linkage analysis in CDKN2A-negative Spanish melanoma-prone families to identify novel melanoma susceptibility loci. We included 68 individuals from 2, 3 and 6 families with 2, 3 and at least 4 melanoma cases. We detected a locus with significant linkage evidence at 11q14.1-q14.3, with a maximum het-TLOD of 3.449 (rs12285365:A>G), using evidence from multiple pedigrees. The genes contained by the subregion with the strongest linkage evidence were: DLG2, PRSS23, FZD4 and TMEM135. We also detected several regions with suggestive linkage evidence (TLOD>1.9) (1q, 6p, 7p, 11q, 12p, 13q) including the region previously detected in melanoma-prone families from Sweden at 3q29. The family specific analysis revealed three loci with suggestive linkage evidence for family #1: 1q31.1-q32.1 (max. TLOD 2.447), 6p24.3-p22.3 (max. TLOD 2.409) and 11q13.3-q21 (max. TLOD 2.654). Future next generation sequencing studies of these regions may allow the identification of new melanoma susceptibility genetic factors.
Project description:The main genetic factors for familial melanoma remain unknown in more than 75% of families. CDKN2A is mutated in around 20% of melanoma-prone families. Other high-risk melanoma susceptibility genes explain less than 3% of families studied to date. We performed the first genome-wide linkage analysis in CDKN2A-negative Spanish melanoma-prone families to identify novel melanoma susceptibility loci. We included 68 individuals from 2, 3 and 6 families with 2, 3 and at least 4 melanoma cases. We detected a locus with significant linkage evidence at 11q14.1-q14.3, with a maximum het-TLOD of 3.449 (rs12285365:A>G), using evidence from multiple pedigrees. The genes contained by the subregion with the strongest linkage evidence were: DLG2, PRSS23, FZD4 and TMEM135. We also detected several regions with suggestive linkage evidence (TLOD>1.9) (1q, 6p, 7p, 11q, 12p, 13q) including the region previously detected in melanoma-prone families from Sweden at 3q29. The family specific analysis revealed three loci with suggestive linkage evidence for family #1: 1q31.1-q32.1 (max. TLOD 2.447), 6p24.3-p22.3 (max. TLOD 2.409) and 11q13.3-q21 (max. TLOD 2.654). Future next generation sequencing studies of these regions may allow the identification of new melanoma susceptibility genetic factors.
Project description:The main genetic factors for familial melanoma remain unknown in >75% of families. CDKN2A is mutated in around 20% of melanoma-prone families. Other high-risk melanoma susceptibility genes explain <3% of families studied to date. We performed the first genome-wide linkage analysis in CDKN2A-negative Spanish melanoma-prone families to identify novel melanoma susceptibility loci. We included 68 individuals from 2, 3, and 6 families with 2, 3, and at least 4 melanoma cases. We detected a locus with significant linkage evidence at 11q14.1-q14.3, with a maximum het-TLOD of 3.449 (rs12285365:A>G), using evidence from multiple pedigrees. The genes contained by the subregion with the strongest linkage evidence were: DLG2, PRSS23, FZD4, and TMEM135. We also detected several regions with suggestive linkage evidence (TLOD >1.9) (1q, 6p, 7p, 11q, 12p, 13q) including the region previously detected in melanoma-prone families from Sweden at 3q29. The family-specific analysis revealed three loci with suggestive linkage evidence for family #1: 1q31.1-q32.1 (max. TLOD 2.447), 6p24.3-p22.3 (max. TLOD 2.409), and 11q13.3-q21 (max. TLOD 2.654). Future next-generation sequencing studies of these regions may allow the identification of new melanoma susceptibility genetic factors.
Project description:BackgroundIn the United States, only approximately 0.4% of all melanomas are diagnosed in patients aged <20 years. To the authors' knowledge, melanoma in pediatric members of melanoma-prone families has not been fully investigated to date. The objective of the current study was to evaluate pediatric patients with melanoma with extensive follow-up in melanoma-prone families with and without cyclin-dependent kinase inhibitor 2A (CDKN2A) mutations.MethodsFor this non-population-based study, families were followed prospectively for up to 40 years. A total of 60 families with ≥ 3 patients with melanoma were included for analysis: 30 CDKN2A mutation-positive (CDKN2A+) and 30 CDKN2A mutation-negative (CDKN2A-) families. Age at the time of first melanoma and number of melanomas were obtained for each patient and summarized by family or sets (CDKN2A + vs CDKN2A-). For set comparisons and categorical variables (occurrence of melanoma in pediatric patients, number of melanomas, number of patients with single or multiple melanomas), the Pearson chi-square or Fisher exact test was used.ResultsRegardless of CDKN2A status, melanoma-prone families were found to have 6-fold to 28-fold higher percentages of patients with pediatric melanoma compared with the general population of patients with melanoma in the United States. Within CDKN2A + families, pediatric patients with melanoma were significantly more likely to have multiple melanomas compared with their relatives who were diagnosed at age >20 years (71% vs 38%, respectively; P = .004). CDKN2A + families had significantly higher percentages of pediatric patients with melanoma compared with CDKN2A- families (11.1% vs 2.5%; P = .004).ConclusionsThese observations have implications for the prevention of melanoma as well as clinical care for its early detection. Children in melanoma-prone families should have careful sun protection from an early age and skin surveillance to reduce their risk of melanoma.
Project description:Primary focal hyperhidrosis (PFH, OMIM %144110) is a genetically influenced condition characterised by excessive sweating. Prevalence varies between 1.0-6.1% in the general population, dependent on ethnicity. The aetiology of PFH remains unclear but an autosomal dominant mode of inheritance, incomplete penetrance and variable phenotypes have been reported. In our study, nine pedigrees (50 affected, 53 non-affected individuals) were included. Clinical characterisation was performed at the German Hyperhidrosis Centre, Munich, by using physiological and psychological questionnaires. Genome-wide parametric linkage analysis with GeneHunter was performed based on the Illumina genome-wide SNP arrays. Haplotypes were constructed using easyLINKAGE and visualised via HaploPainter. Whole-exome sequencing (WES) with 100x coverage in 31 selected members (24 affected, 7 non-affected) from our pedigrees was achieved by next generation sequencing. We identified four genome-wide significant loci, 1q41-1q42.3, 2p14-2p13.3, 2q21.2-2q23.3 and 15q26.3-15q26.3 for PFH. Three pedigrees map to a shared locus at 2q21.2-2q23.3, with a genome-wide significant LOD score of 3.45. The chromosomal region identified here overlaps with a locus at chromosome 2q22.1-2q31.1 reported previously. Three families support 1q41-1q42.3 (LOD = 3.69), two families share a region identical by descent at 2p14-2p13.3 (LOD = 3.15) and another two families at 15q26.3 (LOD = 3.01). Thus, our results point to considerable genetic heterogeneity. WES did not reveal any causative variants, suggesting that variants or mutations located outside the coding regions might be involved in the molecular pathogenesis of PFH. We suggest a strategy based on whole-genome or targeted next generation sequencing to identify causative genes or variants for PFH.