Bi-allelic genetic variants in the translational GTPases GTPBP1 and GTPBP2 cause a distinct identical neurodevelopmental syndrome.

The homologous genes GTPBP1 and GTPBP2 encode GTP-binding proteins 1 and 2, which are involved in ribosomal homeostasis. Pathogenic variants in GTPBP2 were recently shown to be an ultra-rare cause of neurodegenerative or neurodevelopmental disorders (NDDs). Until now, no human phenotype has been linked to GTPBP1. Here, we describe individuals carrying bi-allelic GTPBP1 variants that display an identical phenotype with GTPBP2 and characterize the overall spectrum of GTP-binding protein (1/2)-related disorders. In this study, 20 individuals from 16 families with distinct NDDs and syndromic facial features were investigated by whole-exome (WES) or whole-genome (WGS) sequencing. To assess the functional impact of the identified genetic variants, semi-quantitative PCR, western blot, and ribosome profiling assays were performed in fibroblasts from affected individuals. We also investigated the effect of reducing expression of CG2017, an ortholog of human GTPBP1/2, in the fruit fly Drosophila melanogaster. Individuals with bi-allelic GTPBP1 or GTPBP2 variants presented with microcephaly, profound neurodevelopmental impairment, pathognomonic craniofacial features, and ectodermal defects. Abnormal vision and/or hearing, progressive spasticity, choreoathetoid movements, refractory epilepsy, and brain atrophy were part of the core phenotype of this syndrome. Cell line studies identified a loss-of-function (LoF) impact of the disease-associated variants but no significant abnormalities on ribosome profiling. Reduced expression of CG2017 isoforms was associated with locomotor impairment in Drosophila. In conclusion, bi-allelic GTPBP1 and GTPBP2 LoF variants cause an identical, distinct neurodevelopmental syndrome. Mutant CG2017 knockout flies display motor impairment, highlighting the conserved role for GTP-binding proteins in CNS development across species.

Novel loss-of-function variants expand ABCC9-related intellectual disability and myopathy syndrome.

Loss-of-function mutation of ABCC9, the gene encoding the SUR2 subunit of ATP sensitive-potassium (KATP) channels, was recently associated with autosomal recessive ABCC9-related intellectual disability and myopathy syndrome (AIMS). Here we identify nine additional subjects, from seven unrelated families, harbouring different homozygous loss-of-function variants in ABCC9 and presenting with a conserved range of clinical features. All variants are predicted to result in severe truncations or in-frame deletions within SUR2, leading to the generation of non-functional SUR2-dependent KATP channels. Affected individuals show psychomotor delay and intellectual disability of variable severity, microcephaly, corpus callosum and white matter abnormalities, seizures, spasticity, short stature, muscle fatigability and weakness. Heterozygous parents do not show any conserved clinical pathology but report multiple incidences of intra-uterine fetal death, which were also observed in an eighth family included in this study. In vivo studies of abcc9 loss-of-function in zebrafish revealed an exacerbated motor response to pentylenetetrazole, a pro-convulsive drug, consistent with impaired neurodevelopment associated with an increased seizure susceptibility. Our findings define an ABCC9 loss-of-function-related phenotype, expanding the genotypic and phenotypic spectrum of AIMS and reveal novel human pathologies arising from KATP channel dysfunction.

Biallelic null variants in PNPLA8 cause microcephaly by reducing the number of basal radial glia.

Patatin-like phospholipase domain-containing lipase 8 (PNPLA8), one of the calcium-independent phospholipase A2 enzymes, is involved in various physiological processes through the maintenance of membrane phospholipids. Biallelic variants in PNPLA8 have been associated with a range of paediatric neurodegenerative disorders. However, the phenotypic spectrum, genotype-phenotype correlations and the underlying mechanisms are poorly understood. Here, we newly identified 14 individuals from 12 unrelated families with biallelic ultra-rare variants in PNPLA8 presenting with a wide phenotypic spectrum of clinical features. Analysis of the clinical features of current and previously reported individuals (25 affected individuals across 20 families) showed that PNPLA8-related neurological diseases manifest as a continuum ranging from variable developmental and/or degenerative epileptic-dyskinetic encephalopathy to childhood-onset neurodegeneration. We found that complete loss of PNPLA8 was associated with the more profound end of the spectrum, with congenital microcephaly. Using cerebral organoids generated from human induced pluripotent stem cells, we found that loss of PNPLA8 led to developmental defects by reducing the number of basal radial glial cells and upper-layer neurons. Spatial transcriptomics revealed that loss of PNPLA8 altered the fate specification of apical radial glial cells, as reflected by the enrichment of gene sets related to the cell cycle, basal radial glial cells and neural differentiation. Neural progenitor cells lacking PNPLA8 showed a reduced amount of lysophosphatidic acid, lysophosphatidylethanolamine and phosphatidic acid. The reduced number of basal radial glial cells in patient-derived cerebral organoids was rescued, in part, by the addition of lysophosphatidic acid. Our data suggest that PNPLA8 is crucial to meet phospholipid synthetic needs and to produce abundant basal radial glial cells in human brain development.

New insights into the clinical and molecular spectrum of the MADD-related neurodevelopmental disorder.

Biallelic pathogenic variants in MADD lead to a very rare neurodevelopmental disorder which is phenotypically pleiotropic grossly ranging from severe neonatal hypotonia, failure to thrive, multiple organ dysfunction, and early lethality to a similar but milder phenotype with better survival. Here, we report 5 patients from 3 unrelated Egyptian families in whom 4 patients showed the severe end of the spectrum displaying neonatal respiratory distress, hypotonia and chronic diarrhea while one patient presented with the mild form displaying moderate intellectual disability and myopathy. In addition, we observed distal arthrogryposis and nonspecific structural brain anomalies in all our patients. Interestingly, cerebellar and brainstem hypoplasia were noted in one patient. Whole exome sequencing identified three novel homozygous variants in the MADD gene: two likely pathogenic [c.4321delC p.(Gln1441ArgfsTer46) and c.2620 C > T p.(Arg874Ter)] and one variant of uncertain significance (c.4307 G > A, p.Arg1436Gln). The variants segregated with the disease in all available family members. Our findings confirm that arthrogryposis, genital, cardiac and structural brain anomalies are manifestations of MADD which expand the spectrum of MADD-related neurodevelopmental disorder. Moreover, they further highlight the convergence of MADD variants on different organ systems leading to complex phenotypes.

Delineating the phenotype of PNPLA8-related mitochondriopathies.

Pathogenic variants in PNPLA8 have been described either with congenital onset displaying congenital microcephaly, early onset epileptic encephalopathy and early lethality or childhood neurodegeneration with progressive microcephaly. Moreover, a phenotype comprising adulthood onset cerebellar ataxia and peripheral neuropathy was also reported. To our knowledge, only six patients with biallelic variants in PNPLA8 have been reported so far. Here, we report the clinical and molecular characterizations of three additional patients in whom exome sequencing identified a loss of function variant (c.1231C>T, p.Arg411Ter) in Family I and a missense variant (c.1559T>A, p.Val520Asp) in Family II in PNPLA8. Patient 1 presented with the congenital form of the disease while Patients 2 and 3 showed progressive microcephaly, infantile onset seizures, progressive cortical atrophy, white matter loss, bilateral degeneration of basal ganglia, and cystic encephalomalacia. Therefore, our results add the infantile onset as a new distinct phenotype of the disease and suggest that the site of the variant rather than its type is strongly correlated with the disease onset. In addition, these conditions demonstrate some overlapping features representing a spectrum with clinical features always aligning with different age of onset.

The clinical and genetic landscape of developmental and epileptic encephalopathies in Egyptian children.

Developmental and epileptic encephalopathies (DEEs) are a heterogeneous group of epilepsies characterized by early-onset, refractory seizures associated with developmental regression or impairment, with a heterogeneous genetic landscape including genes implicated in various pathways and mechanisms. We retrospectively studied the clinical and genetic data of patients with genetic DEE who presented at two tertiary centers in Egypt over a 10-year period. Exome sequencing was used for genetic testing. We report 74 patients from 63 unrelated Egyptian families, with a high rate of consanguinity (58%). The most common seizure type was generalized tonic-clonic (58%) and multiple seizure types were common (55%). The most common epilepsy syndrome was early infantile DEE (50%). All patients showed variable degrees of developmental impairment. Microcephaly, hypotonia, ophthalmological involvement and neuroimaging abnormalities were common. Eighteen novel variants were identified and the phenotypes of five DEE genes were expanded with novel phenotype-genotype associations. Obtaining a genetic diagnosis had implications on epilepsy management in 17 patients with variants in 12 genes. In this study, we expand the phenotype and genotype spectrum of DEE in a large single ethnic cohort of patients. Reaching a genetic diagnosis guided precision management of epilepsy in a significant proportion of patients.

Isolated dentinogenesis imperfecta: Novel DSPP variants and insights on genetic counselling.

OBJECTIVE: Dentinogenesis imperfecta (DI) is an inherited dentin defect and may be isolated or associated with disorders such as osteogenesis imperfecta, odontochondrodysplasia Ehler-Danlos and others. Isolated DI is caused mainly by pathogenic variants in DSPP gene and around 50 different variants have been described in this gene. Herein, we report on 19 patients from two unrelated Egyptian families with isolated DI. Additionally, we focused on genetic counselling of the two families. MATERIALS AND METHODS: The patients were examined clinically and dentally. Panoramic X-rays were done to some patients. Whole exome sequencing (WES) and Sanger sequencing were used. RESULTS: WES revealed two new nonsense variants in DSPP gene, c.288T > A (p.Tyr96Ter) and c.255G > A (p.Trp85Ter). Segregation analysis by Sanger sequencing confirmed the presence of the first variant in all affected members of Family 1 while the second variant was confirmed to be de novo in the patient of Family 2. CONCLUSIONS AND CLINICAL RELEVANCE: Our study extends the number of DSPP pathogenic variants and strengthens the fact that DSPP is the most common DI causative gene irrespective of patients' ethnicity. In addition, we provide insights on genetic counseling issues in patients with inherited DSPP variants taking into consideration the variable religion, culture and laws in our society.

Eco-friendly synchronous fluorescence spectrofluorimetric method for simultaneous determination of montelukast sodium and fexofenadine hydrochloride in their antiallergic rhinitis fixed-dose combination tablets.

An innovative, simple, accurate, sensitive, and eco-friendly synchronous fluorescence spectrofluorimetric method has been developed for the simultaneous analysis of montelukast sodium (MON) and fexofenadine hydrochloride (FEX). The method relies on measuring the relative synchronous fluorescence intensity of both drugs using Δλ of 60 nm in methanol at 405 nm for MON and 288 nm for FEX. The experimental parameters influencing the developed method were investigated and optimized. The method was linear over the ranges 0.1-2.0 and 2.0-20.0 µg/ml for MON and FEX, respectively. The limits of detection were 0.018 and 0.441 µg/ml, and the limits of quantitation were 0.055 and 1.336 µg/ml for MON and FEX, respectively. The developed method was applied successfully for the determination of the two drugs in their newly released fixed-dose combination prescribed for the treatment of allergic rhinitis. The mean per cent recoveries were found to be 100.680 ± 0.890 and 100.110 ± 0.940 for MON and FEX, respectively. Furthermore, the method was found to be eco-friendly green as was evaluated according to the Green Analytical Procedure Index tool guidelines and analytical eco-scale.

Papillon-Lefevre syndrome in twelve Egyptian patients: Five novel CTSC variants and functional characterization of a missense variant and its effect on splicing.

OBJECTIVES: describing the clinical features of twelve Egyptian patients with Papillon-Lefever syndrome (PLS). Five novel mutations in the cathepsin C (CTSC) gene are introduced and the phenotype of the syndrome is expanded by the identification of new clinical features. DESIGN: the clinical, oro-dental data of twelve Egyptian patients from seven unrelated families are described. Sequence analysis of the CTSC gene was performed to identify the causative mutaions. RESULTS: Typical PLS features were presented in all patints but with variable severity. One patient showed atypical dental features including dental structural defect, minimal periodontitis, severe gingivitis, and delayed closure of root apices. Another patient presented with arachnodactyly, dystrophic nails, and buphthalmos in the right eye secondary to uncontrolled congenital glaucoma. Mutational analysis of CTSC gene revealed seven distinct homozygous variants including five novel ones: c.285_286delGT (p.Leu96GlufsTer2), c .302 G>C (p.Trp101Ser), c.622_628delCACAGTC (p.H208Efs*11), c.1331delinsAAAAA (p.G444Efs*4) and c .1343 G>A (p.Cys448Tyr). The previously reported missense variant c .757 G>A (p.Ala253Thr) was found in one patient. This variant is very close to the splice region and by functional studies, we proved that it results in exon skipping and early protein truncation (p.R214Sfs*46). CONCLUSION: We report five novel CTSC variants and describe rare and unusual associated clinical and dental findings such as dental structural defects, delayed closure of root apices, and congenital glaucoma. Therefore, our results expand both the phenotypic and mutational spectrum of PLS.

A novel missense variant in CAT gene causing acatalasemia with gangrenous periodontitis (Takahara's disease).

OBJECTIVES: Acatalasemia is a very rare disorder characterized by gangrenous oral ulcerations and is caused by biallelic variants in the CAT gene which encodes the catalase enzyme that decomposes the hydrogen peroxide molecules to remove their toxic effect. We report two siblings from a consanguineous Egyptian family presenting with joint hyperlaxity, loose dentitions with gangrenous periodontitis, and early loss of teeth. STUDY DESIGN: The patients were clinically suspected to have the periodontal type of Ehlers-Danlos syndrome and thus genetic testing of C1S and C1R causative genes was carried out first by Sanger sequencing then exome sequencing (ES) was considered. RESULTS: No pathogenic variants were detected in C1S and C1R genes then ES revealed a new homozygous missense variant in the CAT gene segregating in the family, c .635 T > G (p.Met212Arg). CONCLUSION: We describe the first Egyptian cases with acatalasemia and expand the mutational spectrum of this rare disorder. Premature loss of teeth is an emerging finding in our cases and addresses the hazardous systemic manifestations associated with the disorder. The rarity of inherited orodental diseases renders the accurate diagnosis difficult and complicates the symptoms. Therefore, the use of advanced molecular technologies is highly advisable for early diagnosis and management of patients.

Computed tomography benefits and cost in hemodynamically stable patients with blunt abdominal trauma at an Egyptian University Hospital.

Background: Trauma is a significant cause of mortality, especially among individuals aged between 15 and 44 years, with a substantial burden falling on economically active populations. Low- and middle-income countries (LMICs) bear the burden of trauma-related deaths, accounting for over 90 % globally. In Egypt, trauma rates are increasing, primarily due to road traffic crashes (RTC), affecting males disproportionately. Blunt abdominal trauma, often caused by RTC, can lead to missed intra-abdominal injuries (IAIs) due to atypical symptoms. Computed Tomography (CT) offers high sensitivity and specificity in detecting IAIs, but concerns about cost and radiation exposure exist. Methodology: This study investigates the roles of Focused Assessment with Sonography for Trauma (FAST) and CT in managing blunt abdominal trauma. A retrospective cohort study was conducted on hemodynamically stable patients. Data included patient demographics, trauma details, healthcare decisions, costs, and outcomes. Results: Computed tomography significantly reduced unnecessary laparotomies (12.3% vs. 24.8 %, p = 0.001), shortened hospital stays (4.83±0.71 days vs. 6.15±1.28 days, p = 0.005), and reduced ICU admissions (8 vs. 32, p = 0.023) compared to FAST alone. Overall costs were lower in the CT & FAST Group ($2055.95 vs. $3488.7, p = 0.0001), with no significant difference in missed IAIs. Conclusion: This study highlights the limitations of relying solely on FAST for IAIs and underscores the value of CT in guiding healthcare decisions. Incorporating CT led to reduced negative laparotomies, shorter hospital stays, and fewer ICU admissions. While CT incurs initial costs, its long-term benefits outweigh expenditures, particularly in LMICs. This study provides insights into optimizing diagnostic approaches for blunt abdominal trauma in low-resource settings.

Biallelic variation in the choline and ethanolamine transporter FLVCR1 underlies a pleiotropic disease spectrum from adult neurodegeneration to severe developmental disorders.

FLVCR1 encodes Feline leukemia virus subgroup C receptor 1 (FLVCR1), a solute carrier (SLC) transporter within the Major Facilitator Superfamily. FLVCR1 is a widely expressed transmembrane protein with plasma membrane and mitochondrial isoforms implicated in heme, choline, and ethanolamine transport. While Flvcr1 knockout mice die in utero with skeletal malformations and defective erythropoiesis reminiscent of Diamond-Blackfan anemia, rare biallelic pathogenic FLVCR1 variants are linked to childhood or adult-onset neurodegeneration of the retina, spinal cord, and peripheral nervous system. We ascertained from research and clinical exome sequencing 27 individuals from 20 unrelated families with biallelic ultra-rare missense and predicted loss-of-function (pLoF) FLVCR1 variant alleles. We characterize an expansive FLVCR1 phenotypic spectrum ranging from adult-onset retinitis pigmentosa to severe developmental disorders with microcephaly, reduced brain volume, epilepsy, spasticity, and premature death. The most severely affected individuals, including three individuals with homozygous pLoF variants, share traits with Flvcr1 knockout mice and Diamond-Blackfan anemia including macrocytic anemia and congenital skeletal malformations. Pathogenic FLVCR1 missense variants primarily lie within transmembrane domains and reduce choline and ethanolamine transport activity compared with wild-type FLVCR1 with minimal impact on FLVCR1 stability or subcellular localization. Several variants disrupt splicing in a mini-gene assay which may contribute to genotype-phenotype correlations. Taken together, these data support an allele-specific gene dosage model in which phenotypic severity reflects residual FLVCR1 activity. This study expands our understanding of Mendelian disorders of choline and ethanolamine transport and demonstrates the importance of choline and ethanolamine in neurodevelopment and neuronal homeostasis.

RNA methyltransferase SPOUT1/CENP-32 links mitotic spindle organization with the neurodevelopmental disorder SpADMiSS.

SPOUT1/CENP-32 encodes a putative SPOUT RNA methyltransferase previously identified as a mitotic chromosome associated protein. SPOUT1/CENP-32 depletion leads to centrosome detachment from the spindle poles and chromosome misalignment. Aided by gene matching platforms, we identified 24 individuals with neurodevelopmental delays from 18 families with bi-allelic variants in SPOUT1/CENP-32 detected by exome/genome sequencing. Zebrafish spout1/cenp-32 mutants showed reduction in larval head size with concomitant apoptosis likely associated with altered cell cycle progression. In vivo complementation assays in zebrafish indicated that SPOUT1/CENP-32 missense variants identified in humans are pathogenic. Crystal structure analysis of SPOUT1/CENP-32 revealed that most disease-associated missense variants mapped to the catalytic domain. Additionally, SPOUT1/CENP-32 recurrent missense variants had reduced methyltransferase activity in vitro and compromised centrosome tethering to the spindle poles in human cells. Thus, SPOUT1/CENP-32 pathogenic variants cause an autosomal recessive neurodevelopmental disorder: SpADMiSS ( SPOUT1 Associated Development delay Microcephaly Seizures Short stature) underpinned by mitotic spindle organization defects and consequent chromosome segregation errors.

Correlation between hepatitis C viral load and hepatitis C Core antigenaemia among Egyptians

Hepatitis C virus [HCV] infection is widespread in Egypt. This study compared HCV RNA with HCVcAg for the detection and quantification of viraemia among a sample of Egyptians. Sera from 80 suspected HCV-positive individuals were tested simultaneously for HCV-RNA load using real-time polymerase chain reaction [PCR] and HCVcAg level using ELISA. Of the 80 samples, 25% were HCV-RNA-negative. HCVcAg was detected in all samples: range 0.4-2462 ng/mL, mean 460 [SD 506] ng/mL. The sensitivity and specificity of HCVcAg were 96.7% and 90.9%, respectively. There was a significant correlation between serum HCV-RNA and HCVcAg levels [r = 0.4, P < 0.0001]. HCV-RNA remains the gold standard for diagnosis of active HCV infection but HCVcAg can be used where PCR is not available

L'infection par le virus de l'hépatite C [VHC] est répandue en Egypte. La présente étude compare l'ARN du VHC et l'antigène de la nucléocapside du VHC pour la détection et la quantification de la virémie au sein d'un échantillon d'Egyptiens. Des échantillons sériques prélevés sur 80 personnes suspectes d'être positives au VHC ont été testés simultanément pour la charge d'ARN du VHC au moyen de l'amplification en chaîne par polymérase en temps réel [RT-PCR] et pour les concentrations de l'antigène de la nucléocapside par ELISA. Sur les 80 échantillons, 25% étaient négatifs pour l'ARN du VHC. L'antigène de la nucléocapside a été détecté dans tous les échantillons : les valeurs étaient comprises entre 0,4 et 2462 ng/mL et la moyenne était de 460 ng/mL [E.T. 506]. La sensibilité et la spécificité de l'antigène de la nucléocapside étaient de 96,7% et 90,9% respectivement. Il y avait une corrélation significative entre l'ARN du VHC sérique et les concentrations d'antigène de la nucléocapside [r=0,4, p < 0,0001]. L'ARN du VHC demeure la méthode de référence pour le diagnostic d'infection à VHC active mais l'antigène de la nucléocapside peut être utilisé lorsque la PCR n'est pas disponible