Lynch syndrome (LS) is an autosomal dominant cancer syndrome. It can be caused by mutations of several genes, including MLH1, MSH2, MSH6, PMS2, MLH3 and MSH3, which are responsible for DNA mismatch repair, and LS affects 3-5% of patients with colorectal cancer (CRC). LS is associated with a high risk of cancer in several different locations, although the most commonly affected regions are the colon (20-70% risk), endometrium (15-70% risk), stomach (6-13% risk) and ovaries (4-12% risk). In the present report, the familial case of LS with a detected pathogenic variant in the MSH2 gene is described. The proband was a male who was diagnosed with CRC at the age of 25 years. Genealogy analysis revealed a total of seven affected relatives (including the proband), one of whom (I degree relative, mother) had synchronous cancers (endometrial and ovarian) and five others (of II and III degree relation) had ovarian cancer. Genetic analysis using next generation sequencing detected a heterozygous germline mutation in the MSH2 gene (c.1386 + 1G >A) in the proband and his mother, confirming the diagnosis of LS. The results of the recommended genetic test in an asymptomatic relative of the proband (II degree relative, uncle), found the same familial mutation. Subsequent prophylactic colonoscopy of this relative revealed early stage CRC. The presented case confirms the need for specific genetic analysis, alongside genetic counseling, in hereditary cancer syndromes. Active genetic prophylaxis in patients with LS allows early detection of primary cancers in other locations, and pre-symptomatic genetic analysis of relatives is an option for early diagnosis.

BACKGROUND: Alport syndrome (ATS) is a rare hereditary disease caused by mutations in genes such as COL4A3, COL4A4, and COL4A5. ATS involves a spectrum of phenotypes ranging from isolated hematuria that is nonprogressive to progressive renal disease with extrarenal abnormalities. Although ATS can be combined with other diseases or syndromes, ATS combined with lupus nephritis has not been reported before.
METHODS: A Chinese family with ATS was recruited for the current study. Clinical characteristics (including findings from renal biopsy) of ATS patients were collected from medical records, and potential causative genes were explored by whole-exome sequencing. A heterozygous substitution in intron 22 of COL4A3 (NM_000091 c.2657-1G>A) was found in the patients, which was further confirmed by quantitative polymerase chain reaction.
CONCLUSIONS: Heterozygous substitution of a COL4A3 gene splice site was identified by whole-exome sequencing, revealing the molecular pathogenic basis of this disorder. In general, identification of pathogenic genes can help to fully understand the molecular mechanism of disease and facilitate precise treatment.

Congenital myasthenic syndrome-22 (CMS22, OMIM 616224) is a very rare recessive hereditary disorder. At the moment, ten CMS22 patients are described, with the disorder caused by nine different Loss-of-Function mutations and 14 gross deletions in the PREPL gene. The materials for our study were DNA samples of five family members: two patients with myasthenia, their healthy sibling and parents. Clinical exome analysis was carried out for one patient, then the whole family was checked for target variants with Sanger sequencing, quantitative multiplex ligation-dependent probe amplification, and chromosome 2 microsatellite markers study. To determine the functional significance of the splicing variant, we applied the minigene assay. The cause of the proband\'s disorder is a compound heterozygous state of two previously non-described pathogenic PREPL variants: a c.1528C>T (p.(Arg510Ter)) nonsense mutation and a c.2094G>T pseudo-missense variant, which, simultaneously with a p.(Lys698Asn) amino acid substitution, affects splicing, leading to exon 14 skipping in mRNA. The second patient\'s disorder was caused by a homozygous nonsense c.1528C>T (p.(Arg510Ter)) mutation due to maternal uniparental disomy (UPD) of chromosome 2. In this study, we describe a unique case, in which two siblings with a rare disorder have different pathologic genotypes.

Since the identification of BRCA1 there has only ever been described two bi-allelic mutation carriers, one of whom was subsequently shown to be a mono-allelic carrier. The second patient diagnosed with two BRCA1 mutations appears to be accurate but there remain some questions about the missense variant identified in that patient. In this report we have identified a woman who is a bi-allelic mutation carrier of BRCA1 and provide an explanation as to why this patient has a phenotype very similar to that of any mono-allelic mutation carrier. The splice variant identified in this patient appears to be associated with the up-regulation of a BRCA1 splice variant that rescues the lethality of being a double mutant. The consequences of the findings of this report may have implications for mutation interpretation and that could serve as a model for not only BRCA1 but also for other autosomal dominant disorders that are considered as being embryonically lethal.