An Expanded Biological Repertoire for Ins(3,4,5,6)P4 through its Modulation of ClC-3 Function

Ins(3,4,5,6)P4 inhibits plasma membrane Cl− flux in secretory epithelia [1]. However, in most other mammalian cells, receptor-dependent elevation of Ins(3,4,5,6)P4 levels is an “orphan” response that lacks biological significance [2]. We set out to identify Cl− channel(s) and/or transporter(s) that are regulated by Ins(3,4,5,6)P4 in vivo. Several candidates [3-5] were excluded through biophysical criteria, electrophysiological analysis, and confocal immunofluorescence microscopy. Then, we heterologously expressed ClC-3 in the plasma membrane of HEK293-tsA201 cells; whole-cell patch-clamp analysis showed Ins(3,4,5,6)P4 to inhibit Cl− conductance through ClC-3. Next, we heterologously expressed ClC-3 in the early endosomal compartment of BHK cells; by fluorescence ratio imaging of endocytosed FITC-transferrin, we recorded intra-endosomal pH, an in situ biosensor for Cl− flux across endosomal membranes [6]. A cell-permeant, bioactivatable Ins(3,4,5,6)P4 analog elevated endosomal pH from 6.1 to 6.6, reflecting inhibition of ClC-3. Finally, Ins(3,4,5,6)P4 inhibited endogenous ClC-3 conductance in postsynaptic membranes of neonatal hippocampal neurones. Among other ClC-3 functions that could be regulated by Ins(3,4,5,6)P4 are tumor cell migration [7], apoptosis [8], and inflammatory responses [9]. Ins(3,4,5,6)P4 is a ubiquitous cellular signal with diverse biological actions

Antifungal Susceptibilities of Cryptococcus neoformans

Susceptibility profiles of medically important fungi in less-developed countries remain uncharacterized. We measured the MICs of amphotericin B, 5-flucytosine, fluconazole, itraconazole, and ketoconazole for Cryptococcus neoformans clinical isolates from Thailand, Malawi, and the United States and found no evidence of resistance or MIC profile differences among the countries

Reassessing the association: Evaluation of a polyalanine deletion variant of RUNX2 in non‐syndromic sagittal and metopic craniosynostosis

The RUNT‐related transcription factor RUNX2 plays a critical role in osteoblast differentiation, and alterations to gene dosage cause distinct craniofacial anomalies. Uniquely amongst the RUNT‐related family, vertebrate RUNX2 encodes a polyglutamine/polyalanine repeat (Gln23‐Glu‐Ala17 in humans), with the length of the polyalanine component completely conserved in great apes. Surprisingly, a frequent 6‐amino acid deletion polymorphism, p.(Ala84_Ala89)del, occurs in humans (termed 11A allele), and a previous association study (Cuellar et al. Bone 137:115395;2020) reported that the 11A variant was significantly more frequent in non‐syndromic sagittal craniosynostosis (nsSag; allele frequency [AF] = 0.156; 95% confidence interval [CI] 0.126–0.189) compared to non‐syndromic metopic craniosynostosis (nsMet; AF = 0.068; 95% CI 0.045–0.098). However, the gnomAD v.2.1.1 control population used by Cuellar et al. did not display Hardy–Weinberg equilibrium, hampering interpretation. To re‐examine this association, we genotyped the RUNX2 11A polymorphism in 225 individuals with sporadic nsSag as parent–child trios and 164 singletons with sporadic nsMet, restricting our analysis to individuals of European ancestry. We compared observed allele frequencies to the non‐transmitted alleles in the parent–child trios, and to the genome sequencing data from gnomAD v.4, which display Hardy–Weinberg equilibrium. Observed AFs (and 95% CI) were 0.076 (0.053–0.104) in nsSag and 0.082 (0.055–0.118) in nsMet, compared with 0.062 (0.042–0.089) in non‐transmitted parental alleles and 0.065 (0.063–0.067) in gnomAD v.4.0.0 non‐Finnish European control genomes. In summary, we observed a non‐significant excess, compared to gnomAD data, of 11A alleles in both nsSag (relative risk 1.18, 95% CI 0.83–1.67) and nsMet (relative risk 1.29, 95% CI 0.87–1.92), but we did not replicate the much higher excess of RUNX2 11A alleles in nsSag previously reported (p = 0.0001)

Personalized recurrence risk assessment following the birth of a child with a pathogenic de novo mutation

Following the diagnosis of a paediatric disorder caused by an apparently de novo mutation, a recurrence risk of 1–2% is frequently quoted due to the possibility of parental germline mosaicism; but for any specific couple, this figure is usually incorrect. We present a systematic approach to providing individualized recurrence risk. By combining locus-specific sequencing of multiple tissues to detect occult mosaicism with long-read sequencing to determine the parent-of-origin of the mutation, we show that we can stratify the majority of couples into one of seven discrete categories associated with substantially different risks to future offspring. Among 58 families with a single affected offspring (representing 59 de novo mutations in 49 genes), the recurrence risk for 35 (59%) was decreased below 0.1%, but increased owing to parental mixed mosaicism for 5 (9%)—that could be quantified in semen for paternal cases (recurrence risks of 5.6–12.1%). Implementation of this strategy offers the prospect of driving a major transformation in the practice of genetic counselling

SMAD6 variants in craniosynostosis: genotype and phenotype evaluation

Purpose: Enrichment of heterozygous missense and truncating SMAD6 variants was previously reported in nonsyndromic sagittal and metopic synostosis, and interaction of SMAD6 variants with a common polymorphism near BMP2 (rs1884302) was proposed to contribute to inconsistent penetrance. We determined the occurrence of SMAD6 variants in all types of craniosynostosis, evaluated the impact of different missense variants on SMAD6 function, and tested independently whether rs1884302 genotype significantl

Neue Untersuchungsergebnisse zum alter von dunkelbäuchigen Ringelgänsen Branta b. bernicla

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The phenotypic spectrum of WWOX -related disorders: 20 additional cases of WOREE syndrome and review of the literature

Purpose: Germline WWOX pathogenic variants have been associated with disorder of sex differentiation (DSD), spinocerebellar ataxia (SCA), and WWOX-related epileptic encephalopathy (WOREE syndrome). We review clinical and molecular data on WWOX-related disorders, further describing WOREE syndrome and phenotype/genotype correlations. Methods: We report clinical and molecular findings in 20 additional patients from 18 unrelated families with WOREE syndrome and biallelic pathogenic variants in the WWOX gene. Different molecular screening approaches were used (quantitative polymerase chain reaction/multiplex ligation-dependent probe amplification [qPCR/MLPA], array comparative genomic hybridization [array-CGH], Sanger sequencing, epilepsy gene panel, exome sequencing). Results: Two copy-number variations (CNVs) or two single-nucleotide variations (SNVs) were found respectively in four and nine families, with compound heterozygosity for one SNV and one CNV in five families. Eight novel missense pathogenic variants have been described. By aggregating our patients with all cases reported in the literature, 37 patients from 27 families with WOREE syndrome are known. This review suggests WOREE syndrome is a very severe epileptic encephalopathy characterized by absence of language development and acquisition of walking, early-onset drug-resistant seizures, ophthalmological involvement, and a high likelihood of premature death. The most severe clinical presentation seems to be associated with null genotypes. Conclusion: Germline pathogenic variants in WWOX are clearly associated with a severe early-onset epileptic encephalopathy. We report here the largest cohort of individuals with WOREE syndrome

The contribution of X-linked coding variation to severe developmental disorders

Abstract: Over 130 X-linked genes have been robustly associated with developmental disorders, and X-linked causes have been hypothesised to underlie the higher developmental disorder rates in males. Here, we evaluate the burden of X-linked coding variation in 11,044 developmental disorder patients, and find a similar rate of X-linked causes in males and females (6.0% and 6.9%, respectively), indicating that such variants do not account for the 1.4-fold male bias. We develop an improved strategy to detect X-linked developmental disorders and identify 23 significant genes, all of which were previously known, consistent with our inference that the vast majority of the X-linked burden is in known developmental disorder-associated genes. Importantly, we estimate that, in male probands, only 13% of inherited rare missense variants in known developmental disorder-associated genes are likely to be pathogenic. Our results demonstrate that statistical analysis of large datasets can refine our understanding of modes of inheritance for individual X-linked disorders