Cellular stress due to impairment of collagen prolyl hydroxylation complex is rescued by the chaperone 4-phenylbutyrate

Osteogenesis imperfecta (OI) types VII, VIII and IX, caused by recessive mutations in cartilage associated protein (CRTAP), prolyl-3-hydroxylase 1 (P3H1), and cyclophilin B (CyPB), respectively, are characterized by the synthesis of overmodified collagen. The genes encode for the components of the endoplasmic reticulum (ER) complex responsible for the 3-hydroxylation of specific proline residues in collagen type I. Our study dissects the effects of mutations in the proteins of the complex on cellular homeostasis, using primary fibroblasts from seven recessive OI patients. In all cell lines the intracellular retention of overmodified type I collagen molecules causes ER enlargement associated to the presence of protein aggregates, activation of the PERK branch of the unfolded protein response and apoptotic death. The administration of 4-phenylbutyrate (4-PBA) alleviates cellular stress by restoring ER cisternae size, normalizing the p-PERK/PERK ratio and the expression of apoptotic marker. The drug has also a stimulatory effect on autophagy. We proved that the rescue of cellular homeostasis following 4-PBA treatment is associated to its chaperone activity, since it increases protein secretion, restoring ER proteostasis and reducing PERK activation and cell survival also in presence of autophagy pharmacological inhibition.Our results provide a novel insight into the mechanism of 4-PBA action and demonstrated that the intracellular stress in recessive OI can be tuned by 4-PBA therapy, similarly to what we recently reported for dominant OI, thus allowing a common target for OI forms characterized by overmodified collagen

Mutations in SCNM1 cause orofaciodigital syndrome due to minor intron splicing defects affecting primary cilia

Orofaciodigital syndrome (OFD) is a genetically heterogeneous ciliopathy characterized by anomalies of the oral cavity, face, and digits. We describe individuals with OFD from three unrelated families having bi-allelic loss-of-function variants in SCNM1 as the cause of their condition. SCNM1 encodes a protein recently shown to be a component of the human minor spliceosome. However, so far the effect of loss of SCNM1 function on human cells had not been assessed. Using a comparative transcriptome analysis between fibroblasts derived from an OFD-affected individual harboring SCNM1 mutations and control fibroblasts, we identified a set of genes with defective minor intron (U12) processing in the fibroblasts of the affected subject. These results were reproduced in SCNM1 knockout hTERT RPE-1 (RPE-1) cells engineered by CRISPR-Cas9-mediated editing and in SCNM1 siRNA-treated RPE-1 cultures. Notably, expression of TMEM107 and FAM92A encoding primary cilia and basal body proteins, respectively, and that of DERL2, ZC3H8, and C17orf75, were severely reduced in SCNM1-deficient cells. Primary fibroblasts containing SCNM1 mutations, as well as SCNM1 knockout and SCNM1 knockdown RPE-1 cells, were also found with abnormally elongated cilia. Conversely, cilia length and expression of SCNM1-regulated genes were restored in SCNM1-deficient fibroblasts following reintroduction of SCNM1 via retroviral delivery. Additionally, functional analysis in SCNM1-retrotransduced fibroblasts showed that SCNM1 is a positive mediator of Hedgehog (Hh) signaling. Our findings demonstrate that defective U12 intron splicing can lead to a typical ciliopathy such as OFD and reveal that primary cilia length and Hh signaling are regulated by the minor spliceosome through SCNM1 activity.This work was supported by a grant from the Spanish Ministry of Science and Innovation (PID2019-105620RB-I00/AEI/10.13039/501100011033)

Brachydactyly

Brachydactyly ("short digits") is a general term that refers to disproportionately short fingers and toes, and forms part of the group of limb malformations characterized by bone dysostosis. The various types of isolated brachydactyly are rare, except for types A3 and D. Brachydactyly can occur either as an isolated malformation or as a part of a complex malformation syndrome. To date, many different forms of brachydactyly have been identified. Some forms also result in short stature. In isolated brachydactyly, subtle changes elsewhere may be present. Brachydactyly may also be accompanied by other hand malformations, such as syndactyly, polydactyly, reduction defects, or symphalangism

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Differential diagnosis of mucopolysaccharidosis and oligosaccharidosis of a sample of Egyptian children

Mucopolysaccharidosis (MPS) and oligosaccharidosis are lysosomal storage disorders (LSDs) that share many clinical features. The present study aimed to establish a protocol for the biochemical diagnosis of these disorders and their subtypes in affected Egyptian children as well as in pregnant females, in order to prepare children or fetus for enzyme replacement therapy. Urine, plasma and leukocyte samples were collected from 280 children with symptoms suggestive of LSDs. Fourteen amniotic fluid samples were collected from pregnant females having positive family history or having one affected sibling. Assessment of urinary glycosaminoglycans (GAGs) followed by two dimensional electrophoresis (2-DEP), thin layer chromatographic (TLC) for separation of oligosaccharides and plasma or leukocyte enzyme activity were performed. Six of pregnancies were diagnosed to have affected fetuses. 84 children had abnormal 2-DEP and classified as 26 MPS I, 10 MPS II, 24 MPS III and 24 MPS VI. Two were diagnosed as α-mannosidosis and 2 as GM1 gangliosidosis. In conclusion; MPS should be excluded before suspecting oligosaccharidosis. 2-DEP and TLC alone cannot rule out the diagnosis of either MPS or oligosaccharidosis and confirmation must be done by specific lysosomal enzymatic assay. Analysis of GAGs by 2-DEP in amniotic fluid can be promising method for prenatal diagnosis of MPS. Keywords: Mucopolysaccharidosis, Oligosaccharidosis, Two dimensional electrophoresis, Thin layer chromatography, Enzyme activit

A Novel Loss-of-Sclerostin Function Mutation in a First Egyptian Family with Sclerosteosis

Sclerosteosis is a rare autosomal recessive condition characterized by increased bone density. Mutations in SOST gene coding for sclerostin are linked to sclerosteosis. Two Egyptian brothers with sclerosteosis and their apparently normal consanguineous parents were included in this study. Clinical evaluation and genomic sequencing of the SOST gene were performed followed by in silico analysis of the resulting variation. A novel homozygous frameshift mutation in the SOST gene, characterized as one nucleotide cytosine insertion that led to premature stop codon and loss of functional sclerostin, was identified in the two affected brothers. Their parents were heterozygous for the same mutation. To our knowledge this is the first Egyptian study of sclerosteosis and SOST gene causing mutation

Mutaciones en FAM46A en un paciente con osteogénesis imperfecta

Resumen del póster presentado a la XI Reunión Anual CIBERER, celebrada en Castelldefels, Barcelona del 12 al 14 de marzo de 2018.Osteogénesis imperfecta (OI) es una enfermedad asociada a fragilidad ósea y osteoporosis, producida principalmente por mutaciones heterocigotas en los genes codificantes de las cadenas polipeptídicas de colágeno tipo I, COL1A1 y COL1A2. Asimismo, también existen otras formas recesivas y dominantes de esta enfermedad, las cuales se caracterizan por una alta variabilidad genética. Hasta la fecha se han descrito 19 loci de OI, cuya función está relacionada con el metabolismo del colágeno I; la mineralización de la matriz ósea; o la diferenciación de los osteoblastos. Aquí presentamos un paciente de origen egipcio con una mutación en homocigosis en FAM46A, un nuevo gen recientemente identificado como causante de esta enfermedad, y en cuya publicación ha colaborado nuestro laboratorio. FAM46A codifica una proteína perteneciente a la superfamilia de las nucleotidil-transferasas, pero su función molecular a día de hoy permanece desconocida. No obstante, existen evidencias, incluido un modelo animal generado por mutagénesis ENU publicado con anterioridad, que indican que FAM46A desempeña un papel esencial en el desarrollo óseo.Peer reviewe

BMP1 mutations in autosomal recessive osteogenesis imperfecta

Mutations in BMP1 cause osteogenesis imperfect (OI) type XIII (MIM 614856), a probably not so uncommon form of autosomal recessive OI. (Editor's Note: See Chapters 1 and 2 for discussion of OI types related to specific mutations.) We have studied an Egyptian consanguineous family with two children initially diagnosed as OI type III. They had blue sclera, severe kyphoscoliosis and large umbilical hernia. Genetic analysis of this family performed by homozygosity mapping showed lack of linkage to any of the previously known AR-OI loci but identified a homozygous 10.27. Mb DNA segment on chromosome 8p in both affected children comprising the type I collagen C-propeptide protease gene BMP1. Direct sequencing of BMP1 in the proband revealed a Phe249Leu homozygous missense change within the BMP1/mTLD astacin protease domain. Phe249 is a residue which is invariable in all invertebrate and vertebrate members of the astacin family of metalloproteases. A few months later, using a combination of whole-exome sequencing and filtering for homozygous stretches of identified variants, another mutation was reported by other authors in two affected sibs of a consanguineous family from Turkey. They showed increased bone mineral density and multiple recurrent fractures. The mutation in BMP1, a 34. G>C transversion in exon 1 resulting in a Gly12Arg (G12R) substitution within the signal peptide, impaired protein's localization to the endoplasmic reticulum, the correct post-translational glycosylation and its secretion. BMP1 expands the number of growing genes involved in AR-OI and demonstrates the high genetic complexity of the collagen I pathway disorders.Peer Reviewe