Comprehensive genetic study of cystic fibrosis in Slovak patients in 25 years of genetic diagnostics.

INTRODUCTION: Cystic fibrosis (CF) has one of the longest histories in hereditary disease molecular diagnostics. However, identification of causative mutations in the CFTR gene is complicated by over 2000 currently identified mutations; with more still being discovered. Knowledge of mutation spectrum may improve effective routine diagnostics and is obligatory in mutation-specific treatment. OBJECTIVES: This study presents comprehensive mutation screening of the CFTR gene; with 275 unrelated, clinically confirmed and treated cystic fibrosis (CF) patients diagnosed in 25 years genetic testing in Slovakia. METHODS: Detection of the most common CFTR mutations was performed by ELUCIGENE 29 and ELUCIGENE CF EU2 kits. HRM and dHPLC mutation screening methods with subsequent Sanger sequencing were applied for minor mutation screening, and MLPA analysis for deletion/duplication detection. RESULTS: A total of 70 different mutations were identified, from which the most common mutation F508del accounted for 60.36% of all disease alleles and 8 mutations have currently been observed only in Slovak patients. Two large deletions identified on chromosomes 2 and 22 were further characterized to identify breakpoints. Based on mutation screening results and neonatal screening we estimated incidence in Slovakian newborns at approximately 1:6000-7000. CONCLUSION: In our study, we identified mutations in 98.54% of all disease chromosomes, while 86.54% were identified using ELUCIGENE kits, 0.54% by MLPA analysis and 11.46% by sequencing analysis. Knowledge of the mutation spectrum in genetically diagnosed patients improves possibilities of genetic counseling and cascade screening in the affected families and Slovak population.

Genetic polymorphisms related to testosterone metabolism in intellectually gifted boys.

Prepubertal testosterone levels are lower in intellectually gifted boys. The aim of this pilot study was to analyze potential genetic factors related to testosterone metabolism in control and gifted boys. Intellectually gifted (IQ>130; n = 95) and control (n = 67) boys were genotyped. Polymorphisms of interests were chosen in genes including androgen and estrogen receptors, 5-alpha reductase, aromatase and sex hormone binding globulin. Significant differences between control and gifted boys in genotype distributions were found for ESR2 (rs928554) and SHBG (rs1799941). A significantly lower number of CAG repeats in the AR gene were found in gifted boys. Our results support the role of genetic factors related to testosterone metabolism in intellectual giftedness. Increased androgen signaling might explain previous results of lower testosterone levels in intellectually gifted boys and add to the understanding of variability in cognitive abilities.

Mutation analysis of the CFTR gene in Slovak cystic fibrosis patients by DHPLC and subsequent sequencing: identification of four novel mutations.

Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in Caucasians. Its incidence is approximately 1:2500 newborns. CF is caused by mutations in the transmembrane conductance regulator (CFTR) gene, which encodes an important chloride ion channel. The disease affects the respiratory, digestive and reproductive systems. To date more than 1550 mutations and polymorphisms have been identified throughout the CFTR gene, making the DNA diagnosis more difficult. Rapid accurate identification of CFTR gene mutations is important for confirming the clinical diagnosis, for cascade screening in families at risk for CF, for understanding the correlation between genotype and phenotype, and moreover it is also the only means for prenatal diagnosis. Individuals suspect of CF are in Slovakia presently screened for the presence of 30 common mutations, giving mutation detection rate only approximately 48%. To increase the detection rate we applied a gene scanning approach using DHPLC system for analysing specifically all CFTR exons. The fragments showing abnormal elution profiles were subsequently sequenced to characterize the DNA change. We have identified a total of 28 different mutations up to present not found in Slovak CF patients, and 17 different polymorphisms. Four mutations (G437D, H954P, H1375N, and 3120+33G>T) are novel, not yet found in any other CF patient all over the word.