Molecular genetic analysis of the F11 gene in 14 Turkish patients with factor XI deficiency: identification of novel and recurrent mutations and their inheritance within families.

BACKGROUND: Factor XI (FXI) deficiency is an autosomal bleeding disease associated with genetic defects in the F11 gene which cause decreased FXI levels or impaired FXI function. An increasing number of mutations has been reported in the FXI mutation database, most of which affect the serine protease domain of the protein. FXI is a heterogeneous disorder associated with a variable bleeding tendency and a variety of causative F11 gene mutations. The molecular basis of FXI deficiency in 14 patients from ten unrelated families in Turkey was analysed to establish genotype-phenotype correlations and inheritance of the mutations in the patients' families. MATERIAL AND METHODS: Fourteen index cases with a diagnosis of FXI deficiency and family members of these patients were enrolled into the study. The patients' F11 genes were amplified by polymerase chain reaction and subjected to direct DNA sequencing analysis. The findings were analysed statistically using bivariate correlations, Pearson's correlation coefficient and the nonparametric Mann-Whitney test. RESULTS: Direct DNA sequencing analysis of the F11 genes revealed that all of the 14 patients had a F11 gene mutation. Eight different mutations were identified in the apple 1, apple 2 or serine protease domains, except one which was a splice site mutation. Six of the mutations were recurrent. Two of the mutations were novel missense mutations, p.Val522Gly and p.Cys581Arg, within the catalytic domain. The p.Trp519Stop mutation was observed in two families whereas all the other mutations were specific to a single family. DISCUSSION: Identification of mutations confirmed the genetic heterogeneity of FXI deficiency. Most of the patients with mutations did not have any bleeding complications, whereas some had severe bleeding symptoms. Genetic screening for F11 gene mutations is important to decrease the mortality and morbidity rate associated with FXI deficiency, which can be life-threatening if bleeding occurs in tissues with high fibrinolytic activity.

Exploring the role of miRNAs in the diagnosis of MODY3

Background/aim: MODY3 associated with HNF1A is the most common form of MODY and is clinically misdiagnosed as type 1 diabetes due to similar clinical symptoms. This study aimed to analyze the role of HNF1A-regulated miRNAs as a biomarker in the diagnosis of MODY3. Materials and methods: MIN6 cells were transfected with the HNF1A cDNA expression vector for overexpression or with siRNA specific to HNF1A to silence its expression. The HNF1A-regulated miRNAs were determined by RNA-Seq of the total RNA extract. Expressions of the candidate miRNAs in blood samples of MODY3, type 1 diabetes, and type 2 diabetes patients and in healthy subjects were compared statistically by Mann-Whitney U tests. Results: This study revealed the presence of 238 known HNF1A-regulated miRNAs in MIN6 cells. miR-129-1-3p, miR-200b-3p, and miR-378a-5p were selected as candidate miRNAs. The expression level of miR-378a-5p significantly decreased in type 2 diabetes and MODY3 patients, while miR-200b-3p expression was significantly decreased only in MODY3 patients. Conclusion: Although further studies with larger numbers of patients are required, this study demonstrated that the expression levels of miR-200b-3p and miR-378a-5p decrease in MODY3 patients and suggests that miR-200b-3p is an especially strong candidate to use clinically for selecting suspected MODY3 patients.