Genetic investigation of 93 families with microphthalmia or posterior microphthalmos

Microphthalmia is a developmental eye defect that is highly variable in severity and in its potential for systemic association. Despite the discovery of many disease genes in microphthalmia, at least 50% of patients remain undiagnosed genetically. Here, we describe a cohort of 147 patients (93 families) from our highly consanguineous population with various forms of microphthalmia (including the distinct entity of posterior microphthalmos) that were investigated using a next‐generation sequencing multi‐gene panel (i‐panel) as well as whole exome sequencing and molecular karyotyping. A potentially causal mutation was identified in the majority of the cohort with microphthalmia (61%) and posterior microphthalmos (82%). The identified mutations (55 point mutations, 15 of which are novel) spanned 24 known disease genes, some of which have not or only very rarely been linked to microphthalmia (PAX6, SLC18A2, DSC3 and CNKSR1). Our study has also identified interesting candidate variants in 2 genes that have not been linked to human diseases (MYO10 and ZNF219), which we present here as novel candidates for microphthalmia. In addition to revealing novel phenotypic aspects of microphthalmia, this study expands its allelic and locus heterogeneity and highlights the need for expanded testing of patients with this condition.     

Complete urethral duplication: description of surgical approach mimicking distal epispadias repair

ObjectiveTo present two cases of type IIA urethral duplication and propose a reproducible surgical approach.MethodsTwo cases are presented in this report. The first was a male child with a type IIA1 urethral duplication with two urethral channels arising from the bladder through separate bladder necks coursing to the glans penis. The second infant had a type IIA2 urethral duplication with a single bladder neck. Both children were repaired using a surgical approach that joined both urethral openings into a single orthopic meatus. This was accomplished by incising the common septum and utilizing techniques similar to that of a distal epispadias repair.ResultsAt six months of follow-up both infants are voiding from a single stream without complication. Long-term outcomes remain to be determined.ConclusionsThe technique presented in this report both functionally and cosmetically unites the two urethral meatuses while eliminating the risk of damage to the sphincter.     

A POT1 mutation implicates defective telomere end fill-in and telomere truncations in Coats plus

Coats plus (CP) can be caused by mutations in the CTC1 component of CST, which promotes polymerase α (polα)/primase-dependent fill-in throughout the genome and at telomeres. The cellular pathology relating to CP has not been established. We identified a homozygous POT1 S322L substitution (POT1^CP) in two siblings with CP. POT1^CP induced a proliferative arrest that could be bypassed by telomerase. POT1^CP was expressed at normal levels, bound TPP1 and telomeres, and blocked ATR signaling. POT1^CP was defective in regulating telomerase, leading to telomere elongation rather than the telomere shortening observed in other telomeropathies. POT1^CP was also defective in the maintenance of the telomeric C strand, causing extended 3′ overhangs and stochastic telomere truncations that could be healed by telomerase. Consistent with shortening of the telomeric C strand, metaphase chromosomes showed loss of telomeres synthesized by leading strand DNA synthesis. We propose that CP is caused by a defect in POT1/CST-dependent telomere fill-in. We further propose that deficiency in the fill-in step generates truncated telomeres that halt proliferation in cells lacking telomerase, whereas, in tissues expressing telomerase (e.g., bone marrow), the truncations are healed. The proposed etiology can explain why CP presents with features distinct from those associated with telomerase defects (e.g., dyskeratosis congenita).     

Prenatal paracetamol exposure and risk of asthma and elevated immunoglobulin E in childhood

BACKGROUND: We recently found that paracetamol (acetaminophen) use in late pregnancy was associated with an increased risk of early wheezing in the offspring. OBJECTIVE: To see whether use of paracetamol in late pregnancy is associated with an increased risk of asthma, wheezing and other atopic outcomes in the child at school age. METHODS: In the population-based Avon Longitudinal Study of Parents and Children, we measured associations of paracetamol and aspirin use in late pregnancy (20-32 weeks) with asthma, hayfever, eczema (n = 8511) and wheezing (8381) in the offspring at 69-81 months, and with atopy (positive skin prick test to Dermatophagoides pteronyssinus, cat or grass, n = 6527) and blood total IgE (n = 5148) at 7 years. We used logistic and linear regression to analyse binary outcomes and log-transformed IgE, respectively, controlling for potential confounders. RESULTS: Use of paracetamol, but not aspirin, in late pregnancy was positively associated with asthma (odds ratios (ORs), comparing children whose mothers took paracetamol 'sometimes' and 'most days/daily' with those whose mothers never took it, 1.22 (95% confidence interval (CI): 1.06-1.41) and 1.62 (95% CI: 0.86-3.04), respectively; P trend = 0.0037), wheezing (ORs 1.20 (95% CI: 1.02-1.40) and 1.86 (95% CI: 0.98-3.55), respectively; P trend = 0.011), and total IgE (geometric mean ratios 1.14 (95% CI: 1.03-1.26) and 1.52 (95% CI: 0.98-2.38), respectively; P trend = 0.0034), but not hayfever, eczema or skin test positivity. The proportion of asthma attributable to paracetamol use in late pregnancy, assuming a causal relation, was 7%. CONCLUSION: Paracetamol exposure in late gestation may cause asthma, wheezing and elevated IgE in children of school age.     

Novel 5-flucytosine-resistant clade of Candida dubliniensis from Saudi Arabia and Egypt identified by Cd25 fingerprinting

DNA fingerprinting of Candida dubliniensis isolates using the species-specific probe Cd25 previously showed that this species consists of two distinct groups, termed Cd25 group I and Cd25 group II. The present study investigated the population structure of 30 C. dubliniensis oral isolates from Saudi Arabia and Egypt using Cd25 fingerprinting and rRNA gene internal transcribed spacer region-based genotyping. Cd25 fingerprinting analysis of these isolates revealed two distinct populations, the first of which consisted of 10 closely related genotype 1 isolates (average similarity coefficient [S(AB)] value, 0.86). The second population of 20 isolates was much more heterogeneous (average S(AB) value, 0.35) and consisted of two distinct subpopulations, one of which consisted of genotype 3 isolates (n = 13) and the other of genotype 4 isolates (n = 7). A mixed dendrogram generated from the fingerprint data from the 30 Saudi Arabian and Egyptian isolates, 5 Israeli isolates, and 51 previously characterized international isolates (32 of Cd25 group I and 19 of Cd25 group II) revealed the presence of three distinct main clades. The first corresponded to the previously described Cd25 group I and contained all the Saudi Arabian, Egyptian, and Israeli genotype 1 isolates mixed with international isolates. The second clade corresponded to the previously described Cd25 group II and contained three Israeli isolates, one genotype 2 isolate, one genotype 3 isolate, and a genotype 4 variant isolate, which were mixed with international isolates. The third clade has not been described before and consisted solely of the 20 Saudi Arabian and Egyptian genotype 3 and 4 isolates identified in this study and a previously described genotype 4 Israeli isolate. All 20 Cd25 group III isolates exhibited high-level resistance to 5-flucytosine (MIC > or = 128 microg/ml), whereas all Cd25 group I and Cd25 group II isolates tested (10 Saudi Arabian and Egyptian, 16 Israeli, and 24 international) were susceptible to 5-flucytosine (MIC < or = 0.125 microg/ml). The results of this study show for the first time the presence of a novel 5-flucytosine-resistant clade of C. dubliniensis (Cd25 group III) that is predominant among isolates from Saudi Arabia and Egypt and absent from a previously characterized international collection of 98 isolates from 15 countries.     

The clinical significance of methylenetetrahydrofolate reductase (MTHFR) polymorphisms in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Genetic polymorphisms in the folate metabolic pathway may contribute to the susceptibility to childhood ALL because they affect the DNA synthesis, methylation, and repair. The most common polymorphisms are methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C. The current study aimed at detecting the frequency of these two genetic polymorphisms in de novo ALL patients, and to clarify their impact on the response to induction chemotherapy, as well as treatment toxicity. MTHFR C677T and A1298C polymorphisms were tested in 30 de novo ALL patients by restriction fragment length polymerase chain reaction technique. Thirty normal age- and sex-matched subjects were subjected to the same analysis as a control group. The frequency of MTHFR A1298C gene polymorphism was significantly lower in ALL patients than the controls thus showing a protective effect. The two polymorphisms had no effect on the response to induction chemotherapy. As regards the treatment toxicity, MTHFR C677T polymorphism was associated with marked thrombocytopenia, while A1298C polymorphism was associated with hepatic toxicity. Identifying predictors of methotrexate sensitivity may lead to the development of individualized treatment strategies with improved efficacy and reduced toxicity as well as adjusting the initial methotrexate dose.     

Immunological mechanisms underpinning faecal microbiota transplantation for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease that results from a dysregulated immune response against specific environmental triggers in a genetically predisposed individual. Increasing evidence has indicated a causal role for changes in gut microbiota (dysbiosis) contributing to this immune-mediated intestinal inflammation. These mechanisms involve dysregulation of multiple facets of the host immune pathways that are potentially reversible. Faecal microbiota transplantation (FMT) is the transfer of processed stool from a healthy donor into an individual with an illness. FMT has shown promising results in both animal model experiments and clinical studies in IBD in the resolution of intestinal inflammation. The underlying mechanisms, however, are unclear. Insights from these studies have shown interactions between modulation of dysbiosis via changes in abundances of specific members of the gut microbial community and changes in host immunological pathways. Unravelling these causal relationships has promising potential for a translational therapy role to develop targeted microbial therapies and understand the mechanisms that underpin IBD aetiopathogenesis. In this review, we discuss current evidence for the contribution of gut microbiota in the disruption of intestinal immune homeostasis and immunoregulatory mechanisms that are associated with the resolution of inflammation through FMT in IBD.     

Victims of war—Psychoendocrine evidence for the impact of traumatic stress on psychological well-being of adolescents growing up during the Israeli–Palestinian conflict

Violent conflicts are severe traumatic stressors with detrimental effects on physical and mental health, with children and adolescents being particularly at risk. For the hypothalamic–pituitary–adrenal (HPA) axis, characteristic patterns of dysregulation in trauma-exposed individuals have been shown. This study set out to investigate self-reported mental well-being in Palestinian adolescents growing up during the Israeli–Palestinian conflict. Hair cortisol concentrations (HCC) as a psychoendocrine marker for long-term HPA axis aberrations along with the potential protective factor sense of coherence (SoC; i.e., the global mindset to interpret the world and emerging stressors as comprehensible, manageable, and meaningful) were examined. Between 2014 and 2016, posttraumatic stress disorder (PTSD), depression, anxiety, HCC, and SoC were examined in 233 adolescents aged 11 to 16 from the West Bank. More than half of the participants reported trauma exposure, with 40% fulfilling the criteria of a preliminary PTSD diagnosis and a high prevalence of anxiety and depression. HCC was significantly elevated in the PTSD subgroup compared to the subgroup not exposed to any traumatic events (p = 0.046), with trauma-exposed individuals in between. HCC was further associated with typical sequelae of traumatic stress. Notably, SoC was inversely related to self-reported psychopathology, as well as to HCC in the trauma group. The results illustrate the situation of adolescents exposed to chronic traumatic stress and extend the literature on aberrant HPA axis functioning under such conditions. They also point out a central role of SoC, which may imply new strategies to aid individuals exposed to ongoing conflicts.     

Infective endocarditis due to Salmonella typhi--a case report

Endocarditis is a rare complication of typhoid fever. We report a case in which Salmonella enterica serotype typhi was isolated from a case of endocarditis. The isolate was resistant to ampicillin, chloramphenicol and ciprofloxacin but sensitive to ceftriaxone, amikacin and gentamicin.