TRIT1 deficiency: Two novel patients with four novel variants.

International audienceTRIT1 encodes a tRNA isopentenyl transferase that allows a strong interaction between the mini helix and the codon. Recent reports support the TRIT1 bi-allelic alterations as the cause of an autosomal recessive disorder, named combined oxydative phophorylation deficiency 35, with microcephaly, developmental disability, and epilepsy. The phenotype is due to decreased mitochondrial function, with deficit of i6A37 in cytosolic and mitochondrial tRNA. Only 10 patients have been reported. We report on two new patients with four novel variants, and confirm the published clinical TRIT1 deficient phenotype stressing the possibility of both very severe, with generalized pharmaco-resistant seizures, and mild phenotypes

Molecular signatures of cardiac defects in down syndrome lymphoblastoid cell lines suggest altered ciliome and hedgehog pathways

Forty percent of people with Down syndrome exhibit heart defects, most often an atrioventricular septal defect (AVSD) and less frequently a ventricular septal defect (VSD) or atrial septal defect (ASD). Lymphoblastoid cell lines (LCLs) were established from lymphocytes of individuals with trisomy 21, the chromosomal abnormality causing Down syndrome. Gene expression profiles generated from DNA microarrays of LCLs from individuals without heart defects (CHD-; n = 22) were compared with those of LCLs from patients with cardiac malformations (CHD+; n = 21). After quantile normalization, principal component analysis revealed that AVSD carriers could be distinguished from a combined group of ASD or VSD (ASD+VSD) carriers. From 9,758 expressed genes, we identified 889 and 1,016 genes differentially expressed between CHD- and AVSD and CHD- and ASD+VSD, respectively, with only 119 genes in common. A specific chromosomal enrichment was found in each group of affected genes. Among the differentially expressed genes, more than 65% are expressed in human or mouse fetal heart tissues (GEO dataset). Additional LCLs from new groups of AVSD and ASD+VSD patients were analyzed by quantitative PCR; observed expression ratios were similar to microarray results. Analysis of GO categories revealed enrichment of genes from pathways regulating clathrin-mediated endocytosis in patients with AVSD and of genes involved in semaphorin-plexin-driven cardiogenesis and the formation of cytoplasmic microtubules in patients with ASD-VSD. A pathway-oriented search revealed enrichment in the ciliome for both groups and a specific enrichment in Hedgehog and Jak-stat pathways among ASD+VSD patients. These genes or related pathways are therefore potentially involved in normal cardiogenesis as well as in cardiac malformations observed in individuals with trisomy 21. © 2012 Ripoll et al

Galectin-3 modulates epithelial cell adaptation to stress at the ER-mitochondria interface

International audienceCellular stress response contributes to epithelial defense in adaptation to environment changes. Galectins play a pivotal role in the regulation of this response in malignant cells. However, precise underlying mechanisms are largely unknown. Here we demonstrate that Galectin-3, a pro and anti-apoptotic lectin, is required for setting up a correct cellular response to stress by orchestrating several effects. First, Galectin-3 constitutes a key post-transcriptional regulator of stress-related mRNA regulons coordinating the cell metabolism, the mTORC1 complex or the unfolded protein response (UPR). Moreover, we demonstrated the presence of Galectin-3 with mitochondria-associated membranes (MAM), and its interaction with proteins located at the ER or mitochondrial membranes. There Galectin-3 prevents the activation and recruitment at the mitochondria of the regulator of mitochondria fission DRP-1. Accordingly, loss of Galectin-3 impairs mitochondrial morphology, with more fragmented and round mitochondria, and dynamics both in normal and cancer epithelial cells in basal conditions. Importantly, Galectin-3 deficient cells also display changes of the activity of the mitochondrial respiratory chain complexes, of the mTORC1/S6RP/4EBP1 translation pathway and reactive oxygen species levels. Regarding the ER, Galectin-3 did not modify the activities of the 3 branches of the UPR in basal conditions. However, Galectin-3 favours an adaptative UPR following ER stress induction by Thapsigargin treatment. Altogether, at the ER-mitochondria interface, Galectin-3 coordinates the functioning of the ER and mitochondria, preserves the integrity of mitochondrial network and modulates the ER stress response

Classification of heart defects (CHD+) according to the distribution frequency of their p-values.

<p>Empirical cumulative distributions of p-values for the 2-by-2 Student tests A: AVSD/ASD; B: AVSD/VSD; C: ASD/VSD. Comparisons were obtained for 11 224 tests. The comparison to the uniform distribution shows that there is no overall differential expression between ASD and VSD (less small p-values than for an uniform distribution). Cdf: cumulative distribution function.</p

Transcriptome signature of heart defects.

<p>Comparison of ratios for DE genes up- or down-regulated in the AVSD or ASD+VSD group between (1) array ratio in the Ts21 CHD⁻ vs 2N, (2) array ratio in CHD⁺ vs CHD⁻, (3) q-PCR ratio from different experiments in CHD⁺ vs CHD⁻ using additional samples (total number in parentheses). Gene nomenclature, <i>AUTS2</i>: autism susceptibility candidate 2; <i>CNN2</i>: calponin 2; <i>DSCR3</i>: Down syndrome critical region gene 3; <i>DYNLT3</i>: dynein, light chain, Tctex-type 3; <i>NQO1</i>: NAD(P)H dehydrogenase, quinone 1; <i>OFD1</i>: oral-facial-digital syndrome 1; <i>PDIA4</i>: protein disulfide isomerase family A, member 4; <i>PIGP</i>: phosphatidylinositol glycan anchor biosynthesis, class P; <i>TTC3</i>: tetratricopeptide repeat domain 3; <i>TUBB2B</i>: tubulin, beta 2B; <i>ACTG1</i>: actin, gamma 1; <i>ALDOC</i>: aldolase C, fructose-bisphosphate; <i>CACYBP</i>: calcyclin binding protein; <i>DTYMK</i>: deoxythymidylate kinase (thymidylate kinase); <i>ENO2</i>: enolase 2 (gamma, neuronal); <i>GART</i>: phosphoribosylglycinamide formyltransferase, phosphoribosylglycinamide synthetase, phosphoribosylaminoimidazole synthetase; <i>IFNAR1</i>: interferon (alpha, beta, and omega) receptor 1; <i>PLTP</i>: phospholipid transfer protein; <i>RPL10A</i>: ribosomal protein L10a; <i>TNFAIP2</i>: tumor necrosis factor, alpha-induced protein 2.</p

GO categories in the CDH⁺ DE genes.

<p>Analysis of the enrichment of GO categories for the genes DE in the comparison between AVSD or ASD+VSD set of genes and CHD⁻ set of genes compared to the genes expressed in LCLs. Analysis used GOrilla software with a p-value threshold at 10⁻³. N - is the total number of genes, B - is the total number of genes associated with a specific null, n - is the number of genes in the group with heart defect, b - is the number of genes in the intersection.</p

Principal component analysis of gene expression profiles of LCLs from individuals with DS and with CHD: red- AVSD (n = 7); green- ASD (n = 8); blue- VSD (n = 6).

<p>Red circle indicates AVSD, blue circle indicates ASD and VSD.</p

Genotype–phenotype correlations in Down syndrome identified by array CGH in 30 cases of partial trisomy and partial monosomy chromosome 21

Down syndrome (DS) is one of the most frequent congenital birth defects, and the most common genetic cause of mental retardation. In most cases, DS results from the presence of an extra copy of chromosome 21. DS has a complex phenotype, and a major goal of DS research is to identify genotype–phenotype correlations. Cases of partial trisomy 21 and other HSA21 rearrangements associated with DS features could identify genomic regions associated with specific phenotypes. We have developed a BAC array spanning HSA21q and used array comparative genome hybridization (aCGH) to enable high-resolution mapping of pathogenic partial aneuploidies and unbalanced translocations involving HSA21. We report the identification and mapping of 30 pathogenic chromosomal aberrations of HSA21 consisting of 19 partial trisomies and 11 partial monosomies for different segments of HSA21. The breakpoints have been mapped to within ∼85 kb. The majority of the breakpoints (26 of 30) for the partial aneuploidies map within a 10-Mb region. Our data argue against a single DS critical region. We identify susceptibility regions for 25 phenotypes for DS and 27 regions for monosomy 21. However, most of these regions are still broad, and more cases are needed to narrow down the phenotypic maps to a reasonable number of candidate genomic elements per phenotype

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially