Exome Sequencing Identified a Novel FBN2 Mutation in a Chinese Family with Congenital Contractural Arachnodactyly

Congenital contractural arachnodactyly (CCA) is an autosomal dominant disorder of connective tissue. CCA is characterized by arachnodactyly, camptodactyly, contrature of major joints, scoliosis, pectus deformities, and crumpled ears. The present study aimed to identify the genetic cause of a three-generation Chinese family with CCA. We successfully identified a novel missense mutation p.G1145D in the fibrillin-2 (FBN2) gene as the pathogenic mutation by whole exome sequencing (WES). The p.G1145D mutation occurs in the 12th calcium-binding epidermal growth factor-like (cbEGF) domain. The p.G1145D mutation caused a hydrophobic to hydrophilic substitution, altering the amino acid property from neutral to acidic. Three-dimensional structural analysis showed that this mutation could alter the conformation of the residue side chain, thereby producing steric clashes with spatially adjacent residues, disrupting the formation of H bonds and causing folding destabilization. Therefore, this amino acid appears to play an important role in the structure and function of FBN2. Our results may also provide new insights into the cause and diagnosis of CCA and may have implications for genetic counseling and clinical management

Accurate diagnosis of spinal muscular atrophy and 22q11.2 deletion syndrome using limited deoxynucleotide triphosphates and high-resolution melting

Abstract Background Copy number variation (CNV) has been implicated in the genetics of multiple human diseases. Spinal muscular atrophy (SMA) and 22q11.2 deletion syndrome (22q11.2DS) are two of the most common diseases which are caused by DNA copy number variations. Genetic diagnostics for these conditions would be enhanced by more accurate and efficient methods to detect the relevant CNVs. Methods Competitive PCR with limited deoxynucleotide triphosphates (dNTPs) and high-resolution melting (HRM) analysis was used to detect 22q11.2DS, SMA and SMA carrier status. For SMA, we focused on the copy number of SMN1 gene. For 22q11.2DS, we analyzed CNV for 3 genes (CLTCL1, KLHL22, and PI4KA) which are located between different region-specific low copy repeats. CFTR was used as internal reference gene for all targets. Short PCR products with separated Tms were designed by uMelt software. Results One hundred three clinical patient samples were pretested for possible SMN1 CNV, including carrier status, using multiplex ligation-dependent probe amplification (MLPA) commercial kit as gold standard. Ninety-nine samples consisting of 56 wild-type and 43 22q11.2DS samples were analyzed for CLTCL1, KLHL22, and PI4KA CNV also using MLPA. These samples were blinded and re-analyzed for the same CNVs using the limited dNTPs PCR with HRM analysis and the results were completely consistent with MLPA. Conclusions Limited dNTPs PCR with HRM analysis is an accurate method for detecting SMN1 and 22q11.2 CNVs. This method can be used quickly, reliably, and economically in large population screening for these diseases

Changes of Serum Zinc-α2-Glycoprotein Level and Analysis of Its Related Factors in Gestational Diabetes Mellitus

Previous studies have discovered that zinc-α2-glycoprotein (ZAG) is related to insulin resistance and lipid metabolism. The aim of the study is to explore the change of serum ZAG and its related factors in gestational diabetes mellitus (GDM). Eighty newly diagnosed GDM patients were enrolled in the case group, and 80 normal pregnant women were selected as the control group. The differences of baseline data between the two groups were compared, and the change of serum ZAG level and its relationship with related indexes was analyzed. Compared to the control group, the level of serum ZAG in GDM women decreased (P<0.001). What is more, the serum ZAG level of overweight and normal subjects in two groups was also found to have statistical differences. The Pearson correlation (or Spearman correlation) analysis showed that serum ZAG level was negatively correlated with FPG, FINS, HOMA-IR, and TG (all P<0.05) and positively correlated with HDL (P<0.05). Multiple linear regression showed that HDL and HOMA-IR were independent factors of serum ZAG (P<0.05). The level of serum ZAG in patients with gestational diabetes mellitus decreased, and HDL and HOMA-IR are the influencing factors in the case group

Additional file 2: of Accurate diagnosis of spinal muscular atrophy and 22q11.2 deletion syndrome using limited deoxynucleotide triphosphates and high-resolution melting

22q11.2 region copy number determination by restricted dNTPs/HRM and MLPA. Figure S4. CLTCL1 copy number determination by restricted dNTPs and multiplex PCR. Figure S5. PI4KA/KLHL22 copy number determination by restricted dNTPs and multiplex PCR. Figure S6. MLPA results for normal control and 22q11.2 deletion samples. Table S2. Comparison of 22q11.2 detection results of Limited dNTPs/HRM and MLPA. (PDF 1098 kb

Additional file 1: of Accurate diagnosis of spinal muscular atrophy and 22q11.2 deletion syndrome using limited deoxynucleotide triphosphates and high-resolution melting

Restricted dNTPs /HRM and MLPA results for SMN1 exon7 copy number assessment. Figure S1-S2. SMN1 copy number determination by restricted dNTPs and multiplex PCR. Figure S3. MLPA results for normal control, SMA carrier and SMA samples. Table S1. Comparison of SMN1 detection results of Limited dNTPs/HRM and MLPA. (PDF 1052 kb

MET mutation causes muscular dysplasia and arthrogryposis

Abstract Arthrogryposis is a group of phenotypically and genetically heterogeneous disorders characterized by congenital contractures of two or more parts of the body; the pathogenesis and the causative genes of arthrogryposis remain undetermined. We examined a four‐generation arthrogryposis pedigree characterized by camptodactyly, limited forearm supination, and loss of myofibers in the forearms and hands. By using whole‐exome sequencing, we confirmed MET p.Y1234C mutation to be responsible for arthrogryposis in this pedigree. MET p.Y1234C mutation caused the failure of activation of MET tyrosine kinase. A Met p.Y1232C mutant mouse model was established. The phenotypes of homozygous mice included embryonic lethality and complete loss of muscles that originated from migratory precursors. Heterozygous mice were born alive and showed reduction of the number of myofibers in both appendicular and axial muscles. Defective migration of muscle progenitor cells and impaired proliferation of secondary myoblasts were proven to be responsible for the skeletal muscle dysplasia of mutant mice. Overall, our study shows MET to be a causative gene of arthrogryposis and MET mutation could cause skeletal muscle dysplasia in human beings