Combined NGS approaches identify mutations in the intraflagellar transport gene IFT140 in skeletal ciliopathies with early progressive kidney Disease.

Ciliopathies are genetically heterogeneous disorders characterized by variable expressivity and overlaps between different disease entities. This is exemplified by the short rib-polydactyly syndromes, Jeune, Sensenbrenner, and Mainzer-Saldino chondrodysplasia syndromes. These three syndromes are frequently caused by mutations in intraflagellar transport (IFT) genes affecting the primary cilia, which play a crucial role in skeletal and chondral development. Here, we identified mutations in IFT140, an IFT complex A gene, in five Jeune asphyxiating thoracic dystrophy (JATD) and two Mainzer-Saldino syndrome (MSS) families, by screening a cohort of 66 JATD/MSS patients using whole exome sequencing and targeted resequencing of a customized ciliopathy gene panel. We also found an enrichment of rare IFT140 alleles in JATD compared with nonciliopathy diseases, implying putative modifier effects for certain alleles. IFT140 patients presented with mild chest narrowing, but all had end-stage renal failure under 13 years of age and retinal dystrophy when examined for ocular dysfunction. This is consistent with the severe cystic phenotype of Ift140 conditional knockout mice, and the higher level of Ift140 expression in kidney and retina compared with the skeleton at E15.5 in the mouse. IFT140 is therefore a major cause of cono-renal syndromes (JATD and MSS). The present study strengthens the rationale for IFT140 screening in skeletal ciliopathy spectrum patients that have kidney disease and/or retinal dystrophy.

Serbian high-risk families: extensive results on BRCA mutation spectra and frequency.

Mutations in BRCA genes elevate risk for breast and ovarian cancer. These mutations are population specific. As there are no data on BRCA mutation screening on larger number of probands in Serbia to date, aim of this study was to determine types and frequencies of BRCA mutations in individuals from high-risk families from Serbia, as well as to determine which BRCA mutations may be considered as founder for Serbian population. We analyzed 94 probands and detected 9 frameshift mutations in 12 individuals, 1 benign BRCA2 nonsense mutation and numerous missense and synonymous mutations in both genes. Frequency of frameshift mutations is 12.77%. In addition to two novel mutations detected in our population we reported previously, we detected another novel mutation--c.7283delT in BRCA2 exon 14. None of the detected deleterious mutations may be considered as founder mutations for Serbian population, as each of them was found in no more than two high-risk families. This mutation diversity is most probably due to high migration rate in history of this part of Europe. Interpretation of genetic testing results with missense mutations of unknown clinical importance is very challenging and should be approached with caution, using all available data sources for results' interpretation.

RAD51 135G>C and TP53 Arg72Pro polymorphisms and susceptibility to breast cancer in Serbian women.

Breast cancer is a complex disease with both genetic and environmental factors involved in its etiology. An important role of polymorphisms in genes involved in DNA repair has been reported related to breast cancer risk. We conducted a case-control study in order to investigate the association of RAD51 135G>C and TP53 Arg72Pro polymorphisms with breast cancer in Serbian women.48 BRCA negative women with breast cancer and family history of breast/ovarian cancer (hereditary group), 107 women with breast cancer but without family history of the disease (sporadic group) and 114 healthy women without a history of the disease (control group) were included. Restriction fragment length polymorphism was used for genotyping. Genotype and allelic frequencies, the odds ratio (OR) and the 95 % confidence interval (CI) were calculated as an estimate of relative risk. The Hardy-Weinberg equilibrium was tested using χ(2) test. Significance was considered for p < 0.05. RAD51 135G>C showed statistically significant association of CC genotype and increased breast cancer risk (OR 10.28, 95 % CI 1.12-94.5) in hereditary group of patients compared to the control group. Regarding the TP53 Arg72Pro, we showed statistical significance for ProPro + ProArg comparing to ArgArg (OR 2.34, 95 %, CI 1.17-4.70) in hereditary compared to sporadic group. RAD51 135G>C contributes to hereditary breast cancer in Serbian population, with CC genotype as a risk factor. We also found that carriers of Pro allele of TP53 codon 72 is related to hereditary cancer comparing to sporadic one, which indicates it as a potential risk factor for hereditary form of disease.

Novel BRCA1/2 mutations in Serbian breast and breast-ovarian cancer patients with hereditary predisposition.

Mutations in breast cancer susceptibility (BRCA) genes lead to defects in DNA repair processes resulting in elevated genome instability and predisposing to breast and ovarian cancer. The study was designed to detect mutational spectra of BRCA1/2 genes in a Serbian population. Using automated DNA sequencing, we tested individuals for BRCA mutations, based on positive family history of either breast or ovarian cancer or both. Two novel mutations (c.4765_4784del in BRCA1 exon 15 and c.4367_4368dupTT in BRCA2 exon 11) were detected, in three probands from two different families. These mutations have not been reported previously in the BIC or LOVD databases. Protein products of these mutated alleles lack domains necessary for their DNA repair functions, an indicator that these are deleterious mutations. Neither mutation was found in any proband from 50 other families with hereditary predisposition, so the two mutations are likely family-specific rather than population-specific. Although BRCA1-associated tumors are typically negative for estrogen receptor (ER), progesterone receptor (PR), and ERBB2, the novel BRCA1 mutation identified in this study was detected in a proband with ER- and PR-positive breast cancer. Steroid receptor-positive BRCA-related breast cancer in this proband supports the idea of characteristic pathological features and older age of onset among BRCA1-mutated ER-positive breast cancers.