ABSTRACT
BRCA1/2 mutations play a significant role in cancer pathogenesis and predisposition particularly in breast, ovarian and prostate cancers. Thus, germline analysis of BRCA1 and BRCA2 is essential for clinical management strategies aiming at the identification of recurrent and novel mutations that could be used as a first screening approach. We analyzed germline variants of BRCA1/2 genes for 2168 individuals who had cancer diagnosis or high risk assessment due to BRCAs related cancers, referred to 10 health care centers distributed across 7 regions covering the Turkish landscape. Overall, 68 and 157 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-two novel variants were reported from both genes while BRCA2 showed higher mutational heterogeneity. We herein report the collective data as BRCA Turkish consortium that confirm the molecular heterogeneity in BRCAs among Turkish population, and also as the first study presenting the both geographical, demographical and gene based landscape of all recurrent and novel mutations which some might be a founder effect in comparison to global databases. This wider perspective leads to the most accurate variant interpretations which pave the way for the more precise and efficient management affecting the clinical and molecular aspects.
Subject(s)
Breast Neoplasms , Ovarian Neoplasms , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Breast Neoplasms/genetics , Female , Genes, BRCA2 , Genetic Predisposition to Disease , Germ Cells/pathology , Germ-Line Mutation , Humans , Male , Ovarian Neoplasms/genetics , TurkeyABSTRACT
BACKGROUND: Mutations of the BRCA1/2 genes are associated with increased breast and ovarian cancer. The aim of this study was to investigate the founder mutations of the BRCA1 and BRCA2 genes in the Turkish population in the Aegean region as well as their genotype-phenotype correlations. METHODS: All the patients were provided with BRCA1/2 testing criteria according to the National Comprehensive Cancer Network. QIAseq Targeted DNA Panels were used for the BRCA1/2 coding regions. RESULTS: Of the 181 studied patients, 38 (21%) were found to carry pathogenic or likely pathogenic mutations, while 20 (11%) patients were found to carry variants of unknown significance. The most common pathogenic mutations were NM_000059.4:c.2765dup in the BRCA2 gene and NM_007300.4:c.981_982del and NM_007294.3:c. 5266dup in the BRCA1 gene. p.Lys3326* was the most frequently detected variant of unknown significance (6/ 181). Regarding genotype-phenotype correlations, the NM_007300.4:c.981_982del mutation in BRCA1 gene was found to be milder in terms of breast cancer. The most frequent cancers other than those related to BRCA genes, observed in the relatives of the patients who had pathogenic variants and variants of unknown significance, were endometrium cancer and leukemia, respectively. CONCLUSIONS: NM_007294.3:c.5266dup was found to be a candidate founder mutation in the Turkish population. NM_007300.4:c.981_982del mutation seems to have a milder course in terms of breast cancer. A significantly increased frequency of p.Lys3326* variant in breast cancer and ovarian cancer patients compared with that in the 1,000 Genomes Project suggesting that this variant has a slight effect on BRCA2 function.
Subject(s)
Breast Neoplasms , Ovarian Neoplasms , BRCA1 Protein/genetics , BRCA2 Protein , Breast Neoplasms/genetics , Female , Genes, BRCA1 , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Mutation , Ovarian Neoplasms/genetics , TurkeyABSTRACT
BACKGROUND: Brain-derived neurotrophic factor (BDNF) gene polymorphisms are associated with abnormalities in regulation of BDNF secretion. Studies also linked BDNF polymorphisms with changes in brainstem auditory-evoked response test results. Furthermore, BDNF levels are reduced in tinnitus, psychiatric disorders, depression, dysthymic disorder that may be associated with stress, conversion disorder, and suicide attempts due to crises of life. For this purpose, we investigated whether there is any role of BDNF changes in the pathophysiology of tinnitus. MATERIALS AND METHODS: In this study, we examined the possible effects of BDNF variants in individuals diagnosed with tinnitus for more than 3 months. Fifty-two tinnitus subjects between the ages of 18 and 55, and 42 years healthy control subjects in the same age group, who were free of any otorhinolaryngology and systemic disease, were selected for examination. The intensity of tinnitus and depression was measured using the tinnitus handicap inventory, and the differential diagnosis of psychiatric diagnoses made using the Structured Clinical Interview for Fourth Edition of Mental Disorders. BDNF gene polymorphism was analyzed in the genomic deoxyribonucleic acid (DNA) samples extracted from the venous blood, and the serum levels of BDNF were measured. One-way analysis of variance and Chi-squared tests were applied. RESULTS: Serum BDNF level was found lower in the tinnitus patients than controls, and it appeared that there is no correlation between BDNF gene polymorphism and tinnitus. CONCLUSIONS: This study suggests neurotrophic factors such as BDNF may have a role in tinnitus etiology. Future studies with larger sample size may be required to further confirm our results.
