Syntaxin 4 is essential for hearing in human and zebrafish.

Congenital hearing impairment (HI) is a genetically highly heterogeneous disorder in which prompt recognition and intervention are crucial to optimize outcomes. In this study, we used exome sequencing to investigate a large consanguineous Pakistani family with eight affected individuals showing bilateral severe-to-profound HI. This identified a homozygous splice region variant in STX4 (c.232 + 6T>C), which causes exon skipping and a frameshift, that segregated with HI (two-point logarithm of odds (LOD) score = 5.9). STX4, a member of the syntaxin family, is a component of the SNARE machinery involved in several vesicle transport and recycling pathways. In silico analysis showed that murine orthologue Stx4a is highly and widespread expressed in the developing and adult inner ear. Immunofluorescent imaging revealed localization of STX4A in the cell body, cell membrane and stereocilia of inner and outer hair cells. Furthermore, a morpholino-based knockdown of stx4 in zebrafish showed an abnormal startle response, morphological and developmental defects, and a disrupted mechanotransduction function in neuromast hair cells measured via FM1-43 uptake. Our findings indicate that STX4 dysfunction leads to HI in humans and zebrafish and supports the evolutionary conserved role of STX4 in inner ear development and hair cell functioning.

Actin-bundling protein TRIOBP forms resilient rootlets of hair cell stereocilia essential for hearing.

Inner ear hair cells detect sound through deflection of mechanosensory stereocilia. Each stereocilium is supported by a paracrystalline array of parallel actin filaments that are packed more densely at the base, forming a rootlet extending into the cell body. The function of rootlets and the molecules responsible for their formation are unknown. We found that TRIOBP, a cytoskeleton-associated protein mutated in human hereditary deafness DFNB28, is localized to rootlets. In vitro, purified TRIOBP isoform 4 protein organizes actin filaments into uniquely dense bundles reminiscent of rootlets but distinct from bundles formed by espin, an actin crosslinker in stereocilia. We generated mutant Triobp mice (Triobp(Deltaex8/Deltaex8)) that are profoundly deaf. Stereocilia of Triobp(Deltaex8/Deltaex8) mice develop normally but fail to form rootlets and are easier to deflect and damage. Thus, F-actin bundling by TRIOBP provides durability and rigidity for normal mechanosensitivity of stereocilia and may contribute to resilient cytoskeletal structures elsewhere.

De novo and bi-allelic variants in AP1G1 cause neurodevelopmental disorder with developmental delay, intellectual disability, and epilepsy.

Adaptor protein (AP) complexes mediate selective intracellular vesicular trafficking and polarized localization of somatodendritic proteins in neurons. Disease-causing alleles of various subunits of AP complexes have been implicated in several heritable human disorders, including intellectual disabilities (IDs). Here, we report two bi-allelic (c.737C>A [p.Pro246His] and c.1105A>G [p.Met369Val]) and eight de novo heterozygous variants (c.44G>A [p.Arg15Gln], c.103C>T [p.Arg35Trp], c.104G>A [p.Arg35Gln], c.229delC [p.Gln77Lys∗11], c.399_400del [p.Glu133Aspfs∗37], c.747G>T [p.Gln249His], c.928-2A>C [p.?], and c.2459C>G [p.Pro820Arg]) in AP1G1, encoding gamma-1 subunit of adaptor-related protein complex 1 (AP1γ1), associated with a neurodevelopmental disorder (NDD) characterized by mild to severe ID, epilepsy, and developmental delay in eleven families from different ethnicities. The AP1γ1-mediated adaptor complex is essential for the formation of clathrin-coated intracellular vesicles. In silico analysis and 3D protein modeling simulation predicted alteration of AP1γ1 protein folding for missense variants, which was consistent with the observed altered AP1γ1 levels in heterologous cells. Functional studies of the recessively inherited missense variants revealed no apparent impact on the interaction of AP1γ1 with other subunits of the AP-1 complex but rather showed to affect the endosome recycling pathway. Knocking out ap1g1 in zebrafish leads to severe morphological defect and lethality, which was significantly rescued by injection of wild-type AP1G1 mRNA and not by transcripts encoding the missense variants. Furthermore, microinjection of mRNAs with de novo missense variants in wild-type zebrafish resulted in severe developmental abnormalities and increased lethality. We conclude that de novo and bi-allelic variants in AP1G1 are associated with neurodevelopmental disorder in diverse populations.

Should Transport Ventilators Be Used in Times of Crisis? The Use of Emergency Authorized Nonconventional Ventilators Is Associated With Mortality Among Patients With COVID-19 Acute Respiratory Distress Syndrome.

OBJECTIVES: Nonconventional ventilators (NCVs), defined here as transport ventilators and certain noninvasive positive pressure devices, were used extensively as crisis-time ventilators for intubated patients with COVID-19. We assessed whether there was an association between the use of NCV and higher mortality, independent of other factors. DESIGN: This is a multicenter retrospective observational study. SETTING: The sample was recruited from a single healthcare system in New York. The recruitment period spanned from March 1, 2020, to April 30, 2020. PATIENTS: The sample includes patients who were intubated for COVID-19 acute respiratory distress syndrome (ARDS). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 28-day in-hospital mortality. Multivariable logistic regression was used to derive the odds of mortality among patients managed exclusively with NCV throughout their ventilation period compared with the remainder of the sample while adjusting for other factors. A secondary analysis was also done, in which the mortality of a subset of the sample exclusively ventilated with NCV was compared with that of a propensity score-matched subset of the control group. Exclusive use of NCV was associated with a higher 28-day in-hospital mortality while adjusting for confounders in the regression analysis (odds ratio, 1.41; 95% CI [1.07-1.86]). In the propensity score matching analysis, the mortality of patients exclusively ventilated with NCV was 68.9%, and that of the control was 60.7% ( p = 0.02). CONCLUSIONS: Use of NCV was associated with increased mortality among patients with COVID-19 ARDS. More lives may be saved during future ventilator shortages if more full-feature ICU ventilators, rather than NCVs, are reserved in national and local stockpiles.

Dual AAV-based PCDH15 gene therapy achieves sustained rescue of visual function in a mouse model of Usher syndrome 1F.

Mutations in the PCDH15 gene, encoding protocadherin-15, are among the leading causes of Usher syndrome type 1 (USH1F), and account for up to 12% USH1 cases worldwide. A founder truncating variant of PCDH15 has a ∼2% carrier frequency in Ashkenazi Jews accounting for nearly 60% of their USH1 cases. Although cochlear implants can restore hearing perception in USH1 patients, presently there are no effective treatments for the vision loss due to retinitis pigmentosa. We established a founder allele-specific Pcdh15 knockin mouse model as a platform to ascertain therapeutic strategies. Using a dual-vector approach to circumvent the size limitation of adeno-associated virus, we observed robust expression of exogenous PCDH15 in the retinae of Pcdh15KI mice, sustained recovery of electroretinogram amplitudes and key retinoid oxime, substantially improved light-dependent translocation of phototransduction proteins, and enhanced levels of retinal pigment epithelium-derived enzymes. Thus, our data raise hope and pave the way for future gene therapy trials in USH1F subjects.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2022-June 2023.

Since the establishment of the Global Polio Eradication Initiative in 1988, Pakistan remains one of only two countries (along with Afghanistan) with continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress toward polio eradication during January 2022-June 2023. During 2022, Pakistan reported 20 WPV type 1 (WPV1) cases, all of which occurred within a small geographic area encompassing three districts in south Khyber Pakhtunkhwa. As of June 23, only a single WPV1 case from Bannu district in Khyber Pakhtunkhwa province has been reported in 2023, compared with 13 cases during the same period in 2022. In addition, 11 WPV1 isolates have been reported from various environmental surveillance (ES) sewage sampling sites to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographic scope of poliovirus circulation in Pakistan, the isolation of WPV1 from an ES site in Karachi is cause for concern about the actual geographic limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained innovative efforts to vaccinate children who are regularly missed during SIAs and rapidly responding to any new WPV1 isolations.

Impact of donor-recipient age-difference in adolescent heart transplantation.

INTRODUCTION: The relationship between donor age and adolescent heart transplant outcomes remains incompletely understood. We aimed to explore the effect of donor-recipient age difference on survival after adolescent heart transplantation. METHODS: The United Network for Organ Sharing database was used to identify 2,855 adolescents aged 10-17 years undergoing isolated primary heart transplantation from 1/1/2000 to 12/31/2022. The primary outcome was 10-year post-transplant survival. Multivariable Cox regression identified predictors of mortality after adjusting for donor and recipient characteristics. A restricted cubic spline assessed the non-linear association between donor-recipient age-difference and the adjusted relative mortality hazard. RESULTS: The median donor-recipient age-difference was +3 (range -13 to +47) years, and 17.7% (n = 504) of recipients had an age- difference > 10 years. Recipients with an age-difference > 10 years had a less favorable pre-transplant profile, including a higher incidence of priority status 1A (81.6%, n = 411 vs. 73.6%, n = 1730; p = .01). The 10-year survival rate was 54.6% (95% confidence interval (CI) 48.8- 60.4) among recipients with a donor-recipient age-difference > 10 years and 66.9% (95% CI: 64.4-69.4) among those with an age-difference ≤10 years. An age-difference > 10 years was an independent predictor of mortality (hazard ratio 1.43, 95% CI: 1.18-1.72, p < .001). Spline analysis demonstrated that the adjusted mortality hazard increased with increasingly positive donor-recipient age-difference and became significantly higher at an age-difference of 11 years. CONCLUSION: A donor-recipient age-difference > 11 years is independently associated with higher long-term mortality after adolescent heart transplantation. This finding may help inform acceptable donor selection practice for adolescent heart transplant candidates.

Repeat pediatric heart transplantation: A united network for organ sharing database analysis.

BACKGROUND: A history of congenital heart disease and previous transplantation are each independently associated with worse survival following pediatric heart transplantation. This study aimed to evaluate the characteristics and outcomes of children undergoing repeat heart transplantation in the United States based on the underlying diagnosis. METHODS: The United Network for Organ Sharing database was used to identify 8111 patients aged <18 years undergoing isolated heart transplantation from 2000 to 2021, including 435 (5.4%) repeat transplants. Restricted cubic spline analysis assessed the non-linear relationship between inter-transplant interval and the primary outcome of all-cause mortality or re-transplantation. Multivariable Cox regression assessed the impact of re-transplantation on the primary outcome. Median follow-up was 5.0 (interquartile range 1.9-9.9) years. RESULTS: Repeat transplant patients were older (median age 12 vs. 4 years; p < .001), and less likely to be in UNOS status 1A (66.0%, n = 287 vs. 81.0% n = 6217; p < .001) than primary transplant patients. Freedom from the primary outcome was 51.4% (95% confidence interval [CI] 45.5-57.2) among repeat transplants and 70.5% (95% CI 69.2-71.8) among primary transplants at 10 years (p < .001). Among repeat transplant patients, the relative hazard of the primary outcome became non-significant when the inter-transplant interval >3.6 years. Congenital heart disease was an independent predictor of mortality among primary (HR 1.8, 95% CI 1.6-1.9) but not repeat transplant (HR 1.1, 95% CI .8-1.6) patients. CONCLUSIONS: Long-term outcomes remain poor for patients undergoing repeat heart transplantation, particularly those with an inter-transplant interval <3.6 years. Underlying diagnosis does not impact outcomes after repeat transplantation, after accounting for other risk factors.

Sex-Specific Morphometric Analysis of Ascending Aorta and Aortic Arch for Planning Thoracic Endovascular Aortic Repair: A Retrospective Cohort Study.

OBJECTIVE: In many studies on aortic disease, women are underrepresented. The present study aims to assess sex-specific morphometric differences and gain more insight into endovascular treatment of the ascending aorta (AA) and arch. METHODS: Electrocardiogram-gated cardiac computed tomography scans of 116 consecutive patients who were evaluated for transcatheter aortic valve replacement were retrospectively reviewed. Measurements of the AA and aortic arch were made in multiplanar views, perpendicular to the semi-automatic centerline. Multiple linear regression analysis was performed to identify predictors affecting AA and aortic arch diameter in men and women. Propensity score matching was used to investigate whether sex influences aortic morphology. RESULTS: In both sexes, body surface area (BSA) was identified as a positive predictor and diabetes as a negative predictor for aortic diameters. In men, age was identified as a positive predictor and smoking as a negative predictor for aortic diameters. Propensity score matching identified 40 pairs. Systolic and diastolic mean diameters and AA length were significantly wider in men. On average, male aortas were 7.4% wider than female aortas, both in systole and diastole. CONCLUSIONS: The present analysis demonstrates that, in women, increased BSA is associated with increased aortic arch diameters, while diabetes is associated with decreased AA and arch diameters. In men, increased BSA and age are associated with increased AA and arch diameters, while smoking and diabetes are associated with decreased AA and arch diameters. Men were confirmed to have 7.4% greater AA and arch diameters than women. CLINICAL IMPACT: Men had 7.4% greater ascending aorta and arch diameters than women in a retrospective cohort, gated computed tomography-based study of 116 patients. Sex-specific differences in ascending aortic and arch size should be considered by aortic endovascular device manufacturers and physicians when developing ascending and arch endografts and planning aortic interventions.

Safety outcomes of anti-platelet therapy post coronary artery bypass graft surgery: A systematic review and network meta-analysis of randomized control trials.

BACKGROUND: Antiplatelet therapy is used to decrease the risk of graft failure post coronary artery bypass graft surgery. We aimed to compare dual antiplatelet therapy (DAPT) with monotherapy along with a comparison of Aspirin, Ticagrelor, Aspirin+Ticagrelor (A+T) and Aspirin+Clopidogrel (A+C) to determine the major and minor bleeding risk, risk of postoperative myocardial infarction (MI), stroke, and all-cause mortality (ACM). METHODS: Randomized Controlled Trials comparing the four groups were included. Odds ratio (OR) and Absolute Risk (AR) were employed to assess the mean and standard deviation (SD) with 95% confidence intervals (CI). The Bayesian random-effects model was used for statistical analysis. Risk difference and Cochran Q tests were used to calculate rank probability (RP) and heterogeneity, respectively. RESULTS: We included 10 trials, consisting of 21 arms and 3926 patients. For the risk of major and minor bleed, A + T and Ticagrelor showed the lowest mean value of 0.040 (0.043) and 0.067 (0.073), respectively, and the highest RP of being the safest group. While a direct comparison between DAPT and monotherapy resulted in an OR of 0.57 [0.34, 0.95] for the risk of minor bleed. A + T was found to have the highest RP and the lowest mean value in terms of ACM, MI, and stroke. CONCLUSION: No significant difference was found between monotherapy or dual-antiplatelet therapy for the major bleeding risk safety outcome, however DAPT was found to have a significantly higher rate of minor bleeding complications post-CABG. DAPT should be considered as the antiplatelet modality of choice post-CABG.

Clinical outcomes of different revascularization approaches for patients with multi-vessel coronary artery disease: A network meta-analysis.

BACKGROUND: As surgical techniques continue to evolve, the optimal approach for revascularizing multi-vessel coronary artery disease (CAD) remains a matter of ongoing debate. Accordingly, our objective was to compare and contrast various surgical techniques utilized in the management of multi-vessel CAD. METHODS: A systematic literature review was performed using PubMed, Embase, and Cochrane central register of controlled trials from inception to May 2022. Random-effects network meta-analysis was performed for the primary outcome; target vessel revascularization (TVR), and secondary outcomes; mortality, major adverse cardiac and cerebrovascular events, postoperative myocardial infarction, new-onset atrial fibrillation, stroke, new-onset dialysis, in patients undergoing percutaneous coronary intervention (PCI) with a stent, off-pump coronary bypass graft, on-pump coronary artery bypass graft (ONCABG), hybrid coronary revascularization, minimally-invasive coronary artery bypass, or robot-assisted coronary artery bypass (RCAB) surgeries. RESULTS: A total of 8841 patients were included from 23 studies. The analysis showed that ONCABG had the highest freedom from TVR, with a mean (SD) absolute risk of 0.027 (0.029); although ONCABG was found to be superior to all other methods, it was only significantly better than first-generation stent PCI. While RCAB did not demonstrate significant superiority over other treatments, it showed a greater probability of preventing postoperative complications. Notably, no significant heterogeneity was calculated for any of the reported outcomes. CONCLUSIONS: ONCABG shows a better rank probability compared to all other techniques for preventing TVR, while RCAB offers greater freedom from most postoperative complications. However, given the absence of randomized controlled trials, these results should be interpreted with caution.

Lateral thoracotomy versus sternotomy for left ventricular assist device implantation.

PURPOSE OF REVIEW: Traditionally, left ventricular assist devices (LVADs) are implanted via the standard median sternotomy approach. However, a left thoracotomy approach has been purported to offer physiologic benefits. As a result, utilization of the left thoracotomy for LVAD placement is increasing globally, but the benefits of this approach versus sternotomy are still evolving and debatable. This review compares the median sternotomy and thoracotomy approaches for LVAD placement. RECENT FINDINGS: Recent meta-analyses of LVAD implantation via thoracotomy approach suggest that the thoracotomy approach was associated with a reduced incidence of RVF, bleeding, hospital length of stay (LOS), and mortality [1 ▪▪ ,2 ▪▪ ] . No difference in stroke rates was noted. These results offer support as to the feasibility of a thoracotomy approach for LVAD implantation but also highlight its potential superiority over sternotomy. SUMMARY: The most recent literature supports the use of lateral thoracotomy for placement of left ventricle assist devices compared to median sternotomy. Long-term outcomes from lateral thoracotomy are still unknown, however, short-term results favor lateral thoracotomy approaches for LVAD implantation. While the conventional median sternotomy approach was the original operative technique of choice for LVAD implantation, lateral thoracotomy is quickly emerging as a potentially superior technique.

Bi-allelic Variants in METTL5 Cause Autosomal-Recessive Intellectual Disability and Microcephaly.

Intellectual disability (ID) is a genetically and clinically heterogeneous disorder, characterized by limited cognitive abilities and impaired adaptive behaviors. In recent years, exome sequencing (ES) has been instrumental in deciphering the genetic etiology of ID. Here, through ES of a large cohort of individuals with ID, we identified two bi-allelic frameshift variants in METTL5, c.344_345delGA (p.Arg115Asnfs∗19) and c.571_572delAA (p.Lys191Valfs∗10), in families of Pakistani and Yemenite origin. Both of these variants were segregating with moderate to severe ID, microcephaly, and various facial dysmorphisms, in an autosomal-recessive fashion. METTL5 is a member of the methyltransferase-like protein family, which encompasses proteins with a seven-beta-strand methyltransferase domain. We found METTL5 expression in various substructures of rodent and human brains and METTL5 protein to be enriched in the nucleus and synapses of the hippocampal neurons. Functional studies of these truncating variants in transiently transfected orthologous cells and cultured hippocampal rat neurons revealed no effect on the localization of METTL5 but alter its level of expression. Our in silico analysis and 3D modeling simulation predict disruption of METTL5 function by both variants. Finally, mettl5 knockdown in zebrafish resulted in microcephaly, recapitulating the human phenotype. This study provides evidence that biallelic variants in METTL5 cause ID and microcephaly in humans and highlights the essential role of METTL5 in brain development and neuronal function.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2021-July 2022.

After reporting a single wild poliovirus (WPV) type 1 (WPV1) case in 2021, Pakistan reported 14 cases during April 1-July 31, 2022. Pakistan and Afghanistan are the only countries where endemic WPV transmission has never been interrupted (1). In its current 5-year strategic plan, the Global Polio Eradication Initiative (GPEI) has set a goal of interrupting all WPV1 transmission by the end of 2023 (1-3). The reemergence of WPV cases in Pakistan after 14 months with no case detection has uncovered transmission in southern Khyber Pakhtunkhwa province, the most historically challenging area. This report describes Pakistan's progress toward polio eradication during January 2021-July 2022 and updates previous reports (4,5). As of August 20, 2022, all but one of the 14 WPV1 cases in Pakistan during 2022 have been reported from North Waziristan district in Khyber Pakhtunkhwa. In underimmunized populations, excretion of vaccine virus can, during a period of 12-18 months, lead to reversion to neurovirulence, resulting in circulating vaccine-derived polioviruses (cVDPVs), which can cause paralysis and outbreaks. An outbreak of cVDPV type 2 (cVDPV2), which began in Pakistan in 2019, has been successfully contained; the last case occurred in April 2021 (1,6). Despite program improvements, 400,000-500,000 children continue to be missed during nationwide polio supplementary immunization activities (SIAs),* and recent isolation of poliovirus from sewage samples collected in other provinces suggests wider WPV1 circulation during the ongoing high transmission season. Although vaccination efforts have been recently complicated by months of flooding during the summer of 2022, to successfully interrupt WPV1 transmission in the core reservoirs in southern Khyber Pakhtunkhwa and reach the GPEI goal, emphasis should be placed on further improving microplanning and supervision of SIAs and on systematic tracking and vaccination of persistently missed children in these reservoir areas of Pakistan.

Otitis media susceptibility and shifts in the head and neck microbiome due to SPINK5 variants.

BACKGROUND: Otitis media (OM) susceptibility has significant heritability; however, the role of rare variants in OM is mostly unknown. Our goal is to identify novel rare variants that confer OM susceptibility. METHODS: We performed exome and Sanger sequencing of >1000 DNA samples from 551 multiethnic families with OM and unrelated individuals, RNA-sequencing and microbiome sequencing and analyses of swabs from the outer ear, middle ear, nasopharynx and oral cavity. We also examined protein localisation and gene expression in infected and healthy middle ear tissues. RESULTS: A large, intermarried pedigree that includes 81 OM-affected and 53 unaffected individuals cosegregates two known rare A2ML1 variants, a common FUT2 variant and a rare, novel pathogenic variant c.1682A>G (p.Glu561Gly) within SPINK5 (LOD=4.09). Carriage of the SPINK5 missense variant resulted in increased relative abundance of Microbacteriaceae in the middle ear, along with occurrence of Microbacteriaceae in the outer ear and oral cavity but not the nasopharynx. Eight additional novel SPINK5 variants were identified in 12 families and individuals with OM. A role for SPINK5 in OM susceptibility is further supported by lower RNA counts in variant carriers, strong SPINK5 localisation in outer ear skin, faint localisation to middle ear mucosa and eardrum and increased SPINK5 expression in human cholesteatoma. CONCLUSION: SPINK5 variants confer susceptibility to non-syndromic OM. These variants potentially contribute to middle ear pathology through breakdown of mucosal and epithelial barriers, immunodeficiency such as poor vaccination response, alteration of head and neck microbiota and facilitation of entry of opportunistic pathogens into the middle ear.

Giant right coronary artery to coronary sinus fistula.

BACKGROUND: We describe a giant right coronary artery (RCA) to coronary sinus (CS) fistula in a 59-year-old woman who presented to our institution with right heart enlargement. METHODS: Investigation revealed an ectatic 22mm RCA draining into an enlarged CS, and a Qp:Qs of 2.0. We proceeded with surgery. After initiating cardiopulmonary bypass and electrical arrest, the distal RCA was opened. An opening into the CS was confirmed and closed with a bovine pericardium patch. The RCA origin was triply ligated. Anastomoses of a saphenous vein graft to the posterior descending artery and the right ventricular marginal artery were performed, followed by anastomosis to the ascending aorta. RESULTS: Post-operatively, mixed venous oxygen saturation was 76%. Six months later the patient was doing well. CONCLUSION: Coronary artery fistulas are rare congenital anomalies for which the ideal management strategies remain under study, with surgical repair being the mainstay of treatment in complex, aneurysmal fistulas.

Corneal Structural Changes in Congenital Glaucoma.

OBJECTIVE: To identify corneal structure differences on quantitative high-frequency ultrasound biomicroscopy (UBM) among subjects with congenital glaucoma compared with controls. METHODS: This prospective case-control study evaluated 180 UBM images from 44 eyes of 30 subjects (18 control and 12 glaucoma, mean age 5.2±8.0 years, range 0.2-25.8 years) enrolled in the Pediatric Anterior Segment Imaging and Innovation Study (PASIIS). ImageJ was used to quantify a comprehensive set of corneal structures according to 21 quantitative parameters. Statistical analysis compared corneal measurements in glaucoma subtypes and age-matched controls with significance testing and mixed effects models. RESULTS: Significant differences between congenital glaucoma cases and controls were identified in 16 of 21 measured parameters including angle-to-angle, central and peripheral corneal thicknesses, scleral integrated pixel density, anterior corneal radius of curvature, and posterior corneal radius of curvature. Eight parameters differed significantly between primary congenital glaucoma and glaucoma following congenital cataract surgery. CONCLUSION: Multiple measurable corneal structural differences exist between congenital glaucoma and control eyes, and between primary and secondary congenital glaucoma, including but not limited to corneal width and thickness. The structural differences can be quantified from UBM image analysis. Further studies are needed to determine whether corneal features associated with glaucoma can be used to diagnose or monitor progression of congenital glaucoma.

Genomic knockout of alms1 in zebrafish recapitulates Alström syndrome and provides insight into metabolic phenotypes.

Alström syndrome (OMIM #203800) is an autosomal recessive obesity ciliopathy caused by loss-of-function mutations in the ALMS1 gene. In addition to multi-organ dysfunction, such as cardiomyopathy, retinal degeneration and renal dysfunction, the disorder is characterized by high rates of obesity, insulin resistance and early-onset type 2 diabetes mellitus (T2DM). To investigate the underlying mechanisms of T2DM phenotypes, we generated a loss-of-function deletion of alms1 in the zebrafish. We demonstrate conservation of hallmark clinical characteristics alongside metabolic syndrome phenotypes, including a propensity for obesity and fatty livers, hyperinsulinemia and glucose response defects. Gene expression changes in ß-cells isolated from alms1-/- mutants revealed changes consistent with insulin hypersecretion and glucose sensing failure, which were corroborated in cultured murine ß-cells lacking Alms1. We also found evidence of defects in peripheral glucose uptake and concomitant hyperinsulinemia in the alms1-/- animals. We propose a model in which hyperinsulinemia is the primary and causative defect underlying generation of T2DM associated with alms1 deficiency. These observations support the alms1 loss-of-function zebrafish mutant as a monogenic model for mechanistic interrogation of T2DM phenotypes.

Variants in PUS7 Cause Intellectual Disability with Speech Delay, Microcephaly, Short Stature, and Aggressive Behavior.

We describe six persons from three families with three homozygous protein truncating variants in PUS7: c.89_90del (p.Thr30Lysfs∗20), c.1348C>T (p.Arg450∗), and a deletion of the penultimate exon 15. All these individuals have intellectual disability with speech delay, short stature, microcephaly, and aggressive behavior. PUS7 encodes the RNA-independent pseudouridylate synthase 7. Pseudouridylation is the most abundant post-transcriptional modification in RNA, which is primarily thought to stabilize secondary structures of RNA. We show that the disease-related variants lead to abolishment of PUS7 activity on both tRNA and mRNA substrates. Moreover, pus7 knockout in Drosophila melanogaster results in a number of behavioral defects, including increased activity, disorientation, and aggressiveness supporting that neurological defects are caused by PUS7 variants. Our findings demonstrate that RNA pseudouridylation by PUS7 is essential for proper neuronal development and function.

Biallelic variants in TMEM222 cause a new autosomal recessive neurodevelopmental disorder.

PURPOSE: To elucidate the novel molecular cause in families with a new autosomal recessive neurodevelopmental disorder. METHODS: A combination of exome sequencing and gene matching tools was used to identify pathogenic variants in 17 individuals. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and subcellular localization studies were used to characterize gene expression profile and localization. RESULTS: Biallelic variants in the TMEM222 gene were identified in 17 individuals from nine unrelated families, presenting with intellectual disability and variable other features, such as aggressive behavior, shy character, body tremors, decreased muscle mass in the lower extremities, and mild hypotonia. We found relatively high TMEM222 expression levels in the human brain, especially in the parietal and occipital cortex. Additionally, subcellular localization analysis in human neurons derived from induced pluripotent stem cells (iPSCs) revealed that TMEM222 localizes to early endosomes in the synapses of mature iPSC-derived neurons. CONCLUSION: Our findings support a role for TMEM222 in brain development and function and adds variants in the gene TMEM222 as a novel underlying cause of an autosomal recessive neurodevelopmental disorder.