Trio-based whole-exome sequencing of 200 Chinese patients with keratoconus.

Keratoconus (KC) is a complex corneal disorder with a well-recognized genetic component. In this study, we aimed to expand the genetic spectrum of 200 Chinese patients with keratoconus and their unaffected parents. Trio-based whole-exome sequencing was performed in 200 patients with sporadic keratoconus and their unaffected parents. The variants identified in candidate genes for keratoconus were analyzed using multiple bioinformatics tools. Finally, we identified 7 variants in 5 candidate genes for keratoconus in 5 patients. The c.T464C variant in the IMPDH1 gene was defined as likely pathogenic according to the guidelines of the American College of Medical Genetics and Genomics, and the remaining variants in candidate genes (TRANK1, SLC4A11, CERKL, IFT172) were defined as uncertain significance. Our results expand the genetic spectrum in KC, highlight the genetic heterogeneity of this disease and provide important clues for future functional validation.

A sensorineural hearing loss harboring novel compound heterozygous variant in the TRIOBP gene: A case report.

Background: Autosomal recessive non-syndromic deafness-28 (DFNB28; OMIM #609823) specifically refers to prelingual sensorineural hearing loss (SNHL) resulting from homozygous or compound heterozygous mutations in the TRIO- and F-actin-binding protein, TRIOBP gene. In this report, we present a pediatric patient exhibiting novel compound heterozygous deleterious variants in the TRIOBP gene. Methods: The auditory brainstem response result revealed both left- and right-sided deafness with a threshold of 20 dB normal hearing level in the proband. A comprehensive trio whole exome sequencing (WES) using the Celemics G-Mendeliome Whole Exome Sequencing Panel was employed. Results: The WES analysis revealed compound heterozygous TRIOBP variants in the proband, namely c.1192_1195delCAACinsT/p.Gln398* classified as pathogenic and c.3661C > T/p.Arg1221Trp categorized as a variant of uncertain significance according to American College of Medical Genetics and Genomics guidelines. These variants are considered the most probable cause of the proband's SNHL. Conclusion: TRIOBP isoforms are predominantly expressed in the inner ear, contributing to the formation of stereocilia rootlets. Further investigations are required to fully understand the phenotypic variability and establish the pathogenicity of the identified variant in relation to the TRIOBP gene and SNHL.

Interaction of family SES with children's genetic propensity for cognitive and noncognitive skills: No evidence of the Scarr-Rowe hypothesis for educational outcomes.

This study examines the role of genes and environments in predicting educational outcomes. We test the Scarr-Rowe hypothesis, suggesting that enriched environments enable genetic potential to unfold, and the compensatory advantage hypothesis, proposing that low genetic endowments have less impact on education for children from high socioeconomic status (SES) families. We use a pre-registered design with Netherlands Twin Register data (426 ≤ N individuals ≤ 3875). We build polygenic indexes (PGIs) for cognitive and noncognitive skills to predict seven educational outcomes from childhood to adulthood across three designs (between-family, within-family, and trio) accounting for different confounding sources, totalling 42 analyses. Cognitive PGIs, noncognitive PGIs, and parental education positively predict educational outcomes. Providing partial support for the compensatory hypothesis, 39/42 PGI × SES interactions are negative, with 7 reaching statistical significance under Romano-Wolf and 3 under the more conservative Bonferroni multiple testing corrections (p-value < 0.007). In contrast, the Scarr-Rowe hypothesis lacks empirical support, with just 2 non-significant and 1 significant (not surviving Romano-Wolf) positive interactions. Overall, we emphasise the need for future replication studies in larger samples. Our findings demonstrate the value of merging social-stratification and behavioural-genetic theories to better understand the intricate interplay between genetic factors and social contexts.

Genetic associations and parent-of-origin effects of PVRL1 in non-syndromic cleft lip with or without cleft palate across multiple ethnic populations.

OBJECTIVES: This study investigated the associations of PVRL1 gene variants with non-syndromic cleft lip with or without cleft palate (NSCL/P) by evaluating transmission distortion and parent-of-origin (POO) effects in multiple ethnic populations. METHODS: We conducted allelic and genotypic transmission disequilibrium tests (TDT) on 10 single-nucleotide variants (SNVs) in PVRL1 using data from 142 Korean families with an affected child. POO effects were analyzed using the POO likelihood ratio test, comparing transmission rates of maternally and paternally inherited alleles. To assess generalizability and ethnic heterogeneity, we compared results from Korean families with data from the Center for Craniofacial and Dental Genetics, which included 2,226 individuals from 497 European and 245 Asian trios. RESULTS: TDT analysis identified significant over-transmission of the rs7940667 (G361V) C allele in Korean families (p=0.007), a finding replicated in both Asian (p=6.5×10-7) and European families (p=1.6×10-10). Eight SNVs showed strong TDT evidence in larger Asian and European datasets after multiple comparison corrections (p<0.0073). Of these, 4 SNVs (rs7940667, rs7103685, rs7129848, and rs4409845) showed particularly robust association (p<5×10-8). POO analysis revealed significant maternal over-transmission of the rs10790330-A allele in Korean families (p=0.044). This finding was replicated in European families (p=9.0×10-4). Additionally, 3 other SNVs, rs7129848 (p=0.001) and the linked SNVs rs3935406 and rs10892434 (p=0.025), exhibited maternal over-transmission in the validation datasets. CONCLUSIONS: Our findings provide robust evidence supporting the associations of PVRL1 variants with NSCL/P susceptibility. Further research is necessary to explore the potential clinical applications of these findings.

Exploring the Impact of Genetics in a Large Cohort of Moebius Patients by Trio Whole Exome Sequencing.

Moebius syndrome (MBS) is a rare congenital disorder characterized by non-progressive facial palsy and ocular abduction paralysis. Most cases are sporadic, but also rare familial cases with autosomal dominant transmission and incomplete penetrance/variable expressivity have been described. The genetic etiology of MBS is still unclear: de novo pathogenic variants in REV3L and PLXND1 are reported in only a minority of cases, suggesting the involvement of additional causative genes. With the aim to uncover the molecular causative defect and identify a potential genetic basis of this condition, we performed trio-WES on a cohort of 37 MBS and MBS-like patients. No de novo variants emerged in REV3L and PLXND1. We then proceeded with a cohort analysis to identify possible common causative genes among all patients and a trio-based analysis using an in silico panel of candidate genes. However, identified variants emerging from both approaches were considered unlikely to be causative of MBS, mainly due to the lack of clinical overlap. In conclusion, despite this large cohort, WES failed to identify mutations possibly associated with MBS, further supporting the heterogeneity of this syndrome, and suggesting the need for integrated omics approaches to identify the molecular causes underlying MBS development.

Clinical features and GCDH gene variants in three Chinese families with glutaric aciduria type 1: A case series and literature review.

Aim: To analyze the clinical phenotype and genetic etiology of three cases of glutaric aciduria type 1 (GA1) in Chinese children. Methods: We performed genetic and metabolic testing using tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC/MS), followed by trio whole-exome sequencing (trio-WES) and Sanger sequencing. A literature review on glutaric aciduria type 1 (GA1) in Chinese patients was also conducted. Results: Sequencing results showed each case had compound heterozygous variants in GCDH(NM_000159.4): c.214C > G (p.Arg72Gly) and c.411C > G (p.Tyr137Term) (Case 1), c.214C > G (p.Arg72Gly) and c.1204C > T (p.Arg402Trp) (Case 2), and c.1228G > T (p.Val410Leu) and c.395G > A (p.Arg132Gln) (Case 3). These variants were inherited from their respective parents. Notably, the c.214C > G variant found in two children was a novel variant not previously reported. A review of the literature revealed that, clinically, the majority of patients experienced onset in infancy and early childhood (82%). Additionally, 38.36% were diagnosed through newborn screening, with the primary reasons for the initial visit being delayed development (32.43%) and infections (21.61%). The most common clinical manifestations included increased head circumference (77.19%) and motor developmental delay (65.15%). Biochemically, patients exhibited significant elevations in C5DC (98.51%) and C5DC/C8 (94.87%) in blood, as well as GA (94.37%) and 3OHGA (69.39%) in urine. Radiographically, patients showed a high prevalence of abnormalities in cranial MRI (86.15%) and EEG (73.33%). Genetically, 67 distinct GCDH gene variants were identified among 73 patients, with missense variants being the most prevalent type (73.97%). The most frequent variant was c.1244-2 A > C, observed in 17.12% of cases. Additionally, the majority of variant sites were located in exons 11 (25.37%) and 6 (22.39%). Conclusion: GCDH variants were identified as the causative factors in the three children. The discovery of the novel variant (c.214C > G) expands the spectrum of pathogenic GCDH variants. These findings facilitate the diagnosis and treatment of affected children and provide a basis for genetic counseling and prenatal diagnosis for their families.

Rapid genome sequencing for critically ill infants: an inaugural pilot study from Turkey.

Introduction: Rare and ultra-rare genetic conditions significantly contribute to infant morbidity and mortality, often presenting with atypical features and genetic heterogeneity that complicate management. Rapid genome sequencing (RGS) offers a timely and cost-effective approach to diagnosis, aiding in early clinical management and reducing unnecessary interventions. This pilot study represents the inaugural use of next-generation sequencing (NGS) as a diagnostic instrument for critically ill neonatal and pediatric ICU patients in a Turkish hospital setting. Methods: Ten infants were enrolled based on predefined inclusion criteria, and trio RGS was performed. The mean age of the participants was 124 days, with congenital abnormalities being the most common indication for testing. Three patients had consanguineous parents. The mean turnaround time from enrollment to delivery of results was 169 h, with a diagnostic yield of 50%. Results: Three patients received a definitive molecular diagnosis, impacting their clinical management. Two patients benefited from the exclusion of Mendelian conditions, leading to alternative diagnoses. Discussion: This study demonstrates the feasibility and results of RGS in Turkish hospital settings, emphasizing the importance of timely genetic diagnosis in reducing the diagnostic odyssey for families and improving patient care. Further research is needed to evaluate the cost-effectiveness and applicability of RGS in the Turkish healthcare system for children with diseases of uncertain etiology.

Comparative speed of kill provided by lotilaner (Credelio™), sarolaner (Simparica Trio™), and afoxolaner (NexGard™) to control Amblyomma americanum infestations on dogs.

BACKGROUND: Canine acaricides with rapid onset and sustained activity can reduce pathogen transmission risk and enhance pet owner experience. This randomized, complete block design, investigator-masked study compared the speed of kill of Amblyomma americanum provided by three monthly-use isoxazoline-containing products. METHODS: Eight randomized beagles per group were treated (day 0), per label, with sarolaner (combined with moxidectin and pyrantel, Simparica Trio™), afoxolaner (NexGard™), or lotilaner (Credelio™), or remained untreated. Infestations with 50 adult A. americanum were conducted on days - 7, - 2, 21, and 28, and tick counts were performed on day - 5 (for blocking), and at 4, 8, 12, 24, 48, and 72 h following treatment and subsequent infestations. Efficacy calculations were based on geometric mean live tick counts. A linear mixed model was used for between-group comparisons. RESULTS: On day 0, only lotilaner significantly reduced an A. americanum infestation by 12 h (43.3%; P = 0.002). Efficacy of lotilaner and afoxolaner at 24 h post-treatment was 95.3% and 97.6%, respectively, both significantly different from sarolaner (74%) (P = 0.002, P < 0.001, respectively). On day 21, at 12 h postinfestation, lotilaner efficacy (59.6%) was significantly different from sarolaner (0.0%) (P < 0.001) and afoxolaner (6.3%) (P < 0.001). At 24 h, lotilaner efficacy (97.4%) was significantly different (P < 0.001) from sarolaner and afoxolaner (13.6% and 14.9%, respectively). On day 28, at 12 h postinfestation, lotilaner efficacy (47.8%) was significantly different from sarolaner (17.1%) (P = 0.020) and afoxolaner (9.0%) (P = 0.006). At 24 h, lotilaner efficacy (92.3%) was significantly different from sarolaner 4.9% (P < 0.001) and afoxolaner (0.0%) (P < 0.001). Speed of kill for sarolaner and afoxolaner, but not lotilaner, significantly declined over the study period. Following reinfestation on day 28, neither sarolaner nor afoxolaner reached 90% efficacy by 48 h. By 72 h, sarolaner efficacy was 97.4% and afoxolaner efficacy was 86.3%. Only lotilaner achieved ≥ 90% efficacy by 24 h post-treatment and 24 h postinfestation on days 21 and 28. Time to ≥ 90% efficacy following new infestations consistently occurred 24-48 h earlier for lotilaner compared with sarolaner or afoxolaner. CONCLUSIONS: Credelio (lotilaner) has a more rapid onset of acaricidal activity against A. americanum than Simparica Trio (sarolaner-moxidectin-pyrantel) and NexGard (afoxolaner). Only lotilaner's speed of tick kill is sustained throughout the dosing period.

Mapping of long interspersed element-1 (L1) insertions by TIPseq provides information about sub chromosomal genetic variation in human embryos.

PURPOSE: Retrotransposons play important roles during early development when they are transiently de-repressed during epigenetic reprogramming. Long interspersed element-1 (L1), the only autonomous retrotransposon in humans, comprises 17% of the human genome. We applied the Single Cell Transposon Insertion Profiling by Sequencing (scTIPseq) to characterize and map L1 insertions in human embryos. METHODS: Sixteen cryopreserved, genetically tested, human blastocysts, were accessed from consenting couples undergoing IVF at NYU Langone Fertility Center. Additionally, four trios (father, mother, and embryos) were also evaluated. scTIPseq was applied to map L1 insertions in all samples, using L1 locations reported in the 1000 Genomes as controls. RESULTS: Twenty-nine unknown and unique insertions were observed in the sixteen embryos. Most were intergenic; no insertions were located in exons or immediately upstream of genes. The location or number of unknown insertions did not differ between euploid and aneuploid embryos, suggesting they are not merely markers of aneuploidy. Rather, scTIPseq provides novel information about sub-chromosomal structural variation in human embryos. Trio analyses showed a parental origin of all L1 insertions in embryos. CONCLUSION: Several studies have measured L1 expression at different stages of development in mice, but this study for the first time reports unknown insertions in human embryos that were inherited from one parent, confirming no de novo L1 insertions occurred in parental germline or during embryogenesis. Since one-third of euploid embryo transfers fail, future studies would be useful for understanding whether these sub-chromosomal genetic variants or de novo L1 insertions affect embryo developmental potential.

[Gene-gene/gene-environment interaction of transforming growth factor-ß signaling pathway and the risk of non-syndromic oral clefts].

OBJECTIVE: To explore the association between polymorphisms of transforming growth factor-ß (TGF-ß) signaling pathway and non-syndromic cleft lip with or without cleft palate (NSCL/P) among Asian populations, while considering gene-gene interaction and gene-environment interaction. METHODS: A total of 1 038 Asian NSCL/P case-parent trios were ascertained from an international consortium, which conducted a genome-wide association study using a case-parent trio design to investigate the genes affec-ting risk to NSCL/P. After stringent quality control measures, 343 single nucleotide polymorphism (SNP) spanning across 10 pivotal genes in the TGF-ß signaling pathway were selected from the original genome-wide association study(GWAS) dataset for further analysis. The transmission disequilibrium test (TDT) was used to test for SNP effects. The conditional Logistic regression models were used to test for gene-gene interaction and gene-environment interaction. Environmental factors collected for the study included smoking during pregnancy, passive smoking during pregnancy, alcohol intake during pregnancy, and vitamin use during pregnancy. Due to the low rates of exposure to smoking during pregnancy and alcohol consumption during pregnancy (<3%), only the interaction between maternal smoking during pregnancy and multivitamin supplementation during pregnancy was analyzed. The threshold for statistical significance was rigorously set at P =1.46×10-4, applying Bonferroni correction to account for multiple testing. RESULTS: A total of 23 SNPs in 4 genes yielded nominal association with NSCL/P (P<0.05), but none of these associations was statistically significant after Bonferroni' s multiple test correction. However, there were 6 pairs of SNPs rs4939874 (SMAD2) and rs1864615 (TGFBR2), rs2796813 (TGFB2) and rs2132298 (TGFBR2), rs4147358 (SMAD3) and rs1346907 (TGFBR2), rs4939874 (SMAD2) and rs1019855 (TGFBR2), rs4939874 (SMAD2) and rs12490466 (TGFBR2), rs2009112 (TGFB2) and rs4075748 (TGFBR2) showed statistically significant SNP-SNP interaction (P<1.46×10-4). In contrast, the analysis of gene-environment interactions did not yield any significant results after being corrected by multiple testing. CONCLUSION: The comprehensive evaluation of SNP associations and interactions within the TGF-ß signaling pathway did not yield any direct associations with NSCL/P risk in Asian populations. However, the significant gene-gene interactions identified suggest that the genetic architecture influencing NSCL/P risk may involve interactions between genes within the TGF-ß signaling pathway. These findings underscore the necessity for further investigations to unravel these results and further explore the underlying biological mechanisms.

Dentate Gyrus Morphogenesis is Regulated by an Autism Risk Gene Trio Function in Granule Cells.

Autism Spectrum Disorders (ASDs) are reported as a group of neurodevelopmental disorders. The structural changes of brain regions including the hippocampus were widely reported in autistic patients and mouse models with dysfunction of ASD risk genes, but the underlying mechanisms are not fully understood. Here, we report that deletion of Trio, a high-susceptibility gene of ASDs, causes a postnatal dentate gyrus (DG) hypoplasia with a zigzagged suprapyramidal blade, and the Trio-deficient mice display autism-like behaviors. The impaired morphogenesis of DG is mainly caused by disturbing the postnatal distribution of postmitotic granule cells (GCs), which further results in a migration deficit of neural progenitors. Furthermore, we reveal that Trio plays different roles in various excitatory neural cells by spatial transcriptomic sequencing, especially the role of regulating the migration of postmitotic GCs. In summary, our findings provide evidence of cellular mechanisms that Trio is involved in postnatal DG morphogenesis.

Phenotypic and genetic analysis of children with unexplained neurodevelopmental delay and neurodevelopmental comorbidities in a Chinese cohort using trio-based whole-exome sequencing.

BACKGROUND: Trio-based whole-exome sequencing (trio-WES) enables identification of pathogenic variants, including copy-number variants (CNVs), in children with unexplained neurodevelopmental delay (NDD) and neurodevelopmental comorbidities (NDCs), including autism spectrum disorder (ASD), epilepsy, and attention deficit hyperactivity disorder. Further phenotypic and genetic analysis on trio-WES-tested NDD-NDCs cases may help to identify key phenotypic factors related to higher diagnostic yield of using trio-WES and novel risk genes associated with NDCs in clinical settings. METHODS: In this study, we retrospectively performed phenotypic analysis on 163 trio-WES-tested NDD-NDCs children to determine the phenotypic differences between genetically diagnosed and non-genetically diagnosed groups. Additionally, we conducted genetic analysis of ASD genes with the help of Simons Foundation for Autism Research Institute (SFARI) Gene database to identify novel possible ASD-risk genes underlying genetic NDD conditions. RESULTS: Among these 163 patients, pathogenic variants were identified in 82 cases (82/163, 50.3%), including 20 cases with CNVs. By comparing phenotypic variables between genetically diagnosed group (82 cases) and non-genetically diagnosed group (81 cases) with multivariate binary logistic regression analysis, we revealed that NDD-NDCs cases presenting with severe-profound NDD [53/82 vs 17/81, adjusted-OR (95%CI): 4.865 (2.213 - 10.694), adjusted-P < 0.001] or having multiple NDCs [26/82 vs 8/81, adjusted-OR (95%CI): 3.731 (1.399 - 9.950), adjusted-P = 0.009] or accompanying ASD [64/82 vs 35/81, adjusted-OR (95%CI): 3.256 (1.479 - 7.168), adjusted-P = 0.003] and head circumference abnormality [33/82 vs 11/81, adjusted-OR (95%CI): 2.788 (1.148 - 6.774), adjusted-P = 0.024] were more likely to have a genetic diagnosis using trio-WES. Moreover, 37 genes with monogenetic variants were identified in 48 patients genetically diagnosed with NDD-ASD, and 15 dosage-sensitive genes were identified in 16 individuals with NDD-ASD carrying CNVs. Most of those genes had been proven to be ASD-related genes. However, some of them (9 genes) were not proven sufficiently to correlate with ASD. By literature review and constructing protein-protein interaction networks among these 9 candidate ASD-risk genes and 102 established ASD genes obtained from the SFARI Gene database, we identified CUL4B, KCNH1, and PLA2G6 as novel possible ASD-risk genes underlying genetic NDD conditions. CONCLUSIONS: Trio-WES testing is recommended for patients with unexplained NDD-NDCs that have severe-profound NDD or multiple NDCs, particularly those with accompanying ASD and head circumference abnormality, as these independent factors may increase the likelihood of genetic diagnosis using trio-WES. Moreover, NDD patients with pathogenic variants in CUL4B, KCNH1 and PLA2G6 should be aware of potential risks of developing ASD during their disease courses.

Whole genome sequencing identifies associations for nonsyndromic sagittal craniosynostosis with the intergenic region of BMP2 and noncoding RNA gene LINC01428.

Craniosynostosis (CS) is a major birth defect resulting from premature fusion of cranial sutures. Nonsyndromic CS occurs more frequently than syndromic CS, with sagittal nonsyndromic craniosynostosis (sNCS) presenting as the most common CS phenotype. Previous genome-wide association and targeted sequencing analyses of sNCS have identified multiple associated loci, with the strongest association on chromosome 20. Herein, we report the first whole-genome sequencing study of sNCS using 63 proband-parent trios. Sequencing data for these trios were analyzed using the transmission disequilibrium test (TDT) and rare variant TDT (rvTDT) to identify high-risk rare gene variants. Sequencing data were also examined for copy number variants (CNVs) and de novo variants. TDT analysis identified a highly significant locus at 20p12.3, localized to the intergenic region between BMP2 and the noncoding RNA gene LINC01428. Three variants (rs6054763, rs6054764, rs932517) were identified as potential causal variants due to their probability of being transcription factor binding sites, deleterious combined annotation dependent depletion scores, and high minor allele enrichment in probands. Morphometric analysis of cranial vault shape in an unaffected cohort validated the effect of these three single nucleotide variants (SNVs) on dolichocephaly. No genome-wide significant rare variants, de novo loci, or CNVs were identified. Future efforts to identify risk variants for sNCS should include sequencing of larger and more diverse population samples and increased omics analyses, such as RNA-seq and ATAC-seq.

Detection of autism spectrum disorder-related pathogenic trio variants by a novel structure-based approach.

BACKGROUND: Glutamatergic synapse dysfunction is believed to underlie the development of Autism Spectrum Disorder (ASD) and Intellectual Disability (ID) in many individuals. However, identification of genetic markers that contribute to synaptic dysfunction in these individuals is notoriously difficult. Based on genomic analysis, structural modeling, and functional data, we recently established the involvement of the TRIO-RAC1 pathway in ASD and ID. Furthermore, we identified a pathological de novo missense mutation hotspot in TRIO's GEF1 domain. ASD/ID-related missense mutations within this domain compromise glutamatergic synapse function and likely contribute to the development of ASD/ID. The number of ASD/ID cases with mutations identified within TRIO's GEF1 domain is increasing. However, tools for accurately predicting whether such mutations are detrimental to protein function are lacking. METHODS: Here we deployed advanced protein structural modeling techniques to predict potential de novo pathogenic and benign mutations within TRIO's GEF1 domain. Mutant TRIO-9 constructs were generated and expressed in CA1 pyramidal neurons of organotypic cultured hippocampal slices. AMPA receptor-mediated postsynaptic currents were examined in these neurons using dual whole-cell patch clamp electrophysiology. We also validated these findings using orthogonal co-immunoprecipitation and fluorescence lifetime imaging (FLIM-FRET) experiments to assay TRIO mutant overexpression effects on TRIO-RAC1 binding and on RAC1 activity in HEK293/T cells. RESULTS: Missense mutations in TRIO's GEF1 domain that were predicted to disrupt TRIO-RAC1 binding or stability were tested experimentally and found to greatly impair TRIO-9's influence on glutamatergic synapse function. In contrast, missense mutations in TRIO's GEF1 domain that were predicted to have minimal effect on TRIO-RAC1 binding or stability did not impair TRIO-9's influence on glutamatergic synapse function in our experimental assays. In orthogonal assays, we find most of the mutations predicted to disrupt binding display loss of function but mutants predicted to disrupt stability do not reflect our results from neuronal electrophysiological data. LIMITATIONS: We present a method to predict missense mutations in TRIO's GEF1 domain that may compromise TRIO function and test for effects in a limited number of assays. Possible limitations arising from the model systems employed here can be addressed in future studies. Our method does not provide evidence for whether these mutations confer ASD/ID risk or the likelihood that such mutations will result in the development of ASD/ID. CONCLUSIONS: Here we show that a combination of structure-based computational predictions and experimental validation can be employed to reliably predict whether missense mutations in the human TRIO gene impede TRIO protein function and compromise TRIO's role in glutamatergic synapse regulation. With the growing accessibility of genome sequencing, the use of such tools in the accurate identification of pathological mutations will be instrumental in diagnostics of ASD/ID.

Hybrid de novo and haplotype-resolved genome assembly of Vechur cattle - elucidating genetic variation.

Cattle contribute to the nutritional needs and economy of a place. The performance and fitness of cattle depend on the response and adaptation to local climatic conditions. Genomic and genetic studies are important for advancing cattle breeding, and availability of relevant reference genomes is essential. In the present study, the genome of a Vechur calf was sequenced on both short-read Illumina and long-read Nanopore sequencing platforms. The hybrid de novo assembly approach was deployed to obtain an average contig length of 1.97 Mbp and an N50 of 4.94 Mbp. By using a short-read genome sequence of the corresponding sire and dam, a haplotype-resolved genome was also assembled. In comparison to the taurine reference genome, we found 28,982 autosomal structural variants and 16,926,990 SNVs, with 883,544 SNVs homozygous in the trio samples. Many of these SNPs have been reported to be associated with various QTLs including growth, milk yield, and milk fat content, which are crucial determinants of cattle production. Furthermore, population genotype data analysis indicated that the present sample belongs to an Indian cattle breed forming a unique cluster of Bos indicus. Subsequent FST analysis revealed differentiation of the Vechur cattle genome at multiple loci, especially those regions related to whole body growth and cell division, especially IGF1, HMGA2, RRM2, and CD68 loci, suggesting a possible role of these genes in its small stature and better disease resistance capabilities in comparison with the local crossbreeds. This provides an opportunity to select and engineer cattle breeds optimized for local conditions.

RNA analysis and computer-aided facial phenotyping help to classify a novel TRIO splice site variant.

Pathogenic variants in TRIO, encoding the guanine nucleotide exchange factor, are associated with two distinct neurodevelopmental delay phenotypes: gain-of-function missense mutations within the spectrin repeats are causative for a severe developmental delay with macrocephaly (MIM: 618825), whereas loss-of-function missense variants in the GEF1 domain and truncating variants throughout the gene lead to a milder developmental delay and microcephaly (MIM: 617061). In three affected family members with mild intellectual disability/NDD and microcephaly, we detected a novel heterozygous TRIO variant at the last coding base of exon 31 (NM_007118.4:c.4716G>A). RNA analysis from patient-derived lymphoblastoid cells confirmed aberrant splicing resulting in the skipping of exon 31 (r.4615_4716del), leading to an in-frame deletion in the first Pleckstrin homology subdomain of the GEF1 domain: p.(Thr1539_Lys1572del). To test for a distinct gestalt, facial characteristics of the family members and 41 previously published TRIO cases were systematically evaluated via GestaltMatcher. Computational analysis of the facial gestalt suggests a distinguishable facial TRIO-phenotype not outlined in the existing literature.

Phasing Diploid Genome Assembly Graphs with Single-Cell Strand Sequencing.

Haplotype information is crucial for biomedical and population genetics research. However, current strategies to produce de-novo haplotype-resolved assemblies often require either difficult-to-acquire parental data or an intermediate haplotype-collapsed assembly. Here, we present Graphasing, a workflow which synthesizes the global phase signal of Strand-seq with assembly graph topology to produce chromosome-scale de-novo haplotypes for diploid genomes. Graphasing readily integrates with any assembly workflow that both outputs an assembly graph and has a haplotype assembly mode. Graphasing performs comparably to trio-phasing in contiguity, phasing accuracy, and assembly quality, outperforms Hi-C in phasing accuracy, and generates human assemblies with over 18 chromosome-spanning haplotypes.

Sudden death with cardiac involvement in a neonate with carnitine-acylcarnitine translocase deficiency.

A female neonate born with normal Apgar scores at 38+2 weeks of gestational age unexpectedly passed away within less than 30 hours after birth. The situation mirrored her brother's earlier demise within 24 hours post-delivery, suggesting a possible genetic disorder. Gross examination revealed widespread cyanosis and distinct yellowish changes on the cardiac ventricles. Histopathological examination disclosed lipid accumulation in the liver, heart, and kidneys. Tandem mass spectrometry detected elevated levels of 10 amino acids and 14 carnitines in cardiac blood. Trio-whole genome sequencing (Trio-WGS) identified the SLC25A20 c.199-10T>G mutation associated with carnitine-acylcarnitine translocase disease (CACTD), a type of fatty acid oxidation disorders (FAODs) with a potential for sudden death. Further validation of gene expression confirmed the functional deficiency of SLC25A20, ultimately diagnosing CACTD as the underlying cause of the neonate's demise. This case highlights the importance of prenatal metabolic and genetic screening for prospective parents and emphasizes the need for forensic doctors to integrate metabolomic and genomic investigations into autopsies for suspected inherited metabolic diseases.

Identification of genetic causes in children with unexplained epilepsy based on trio-whole exome sequencing.

Genotype and clinical phenotype analyses of 128 children were performed based on whole exome sequencing (WES), providing a reference for the provision of genetic counseling and the precise diagnosis and treatment of epilepsy. A total of 128 children with unexplained epilepsy were included in this study, and all their clinical data were analyzed. The children's treatments, epilepsy control, and neurodevelopmental levels were regularly followed up every 3 months. The genetic diagnostic yield of the 128 children with epilepsy is 50.8%, with an SNV diagnostic yield of 39.8% and a CNV diagnostic yield of 12.5%. Among the 128 children with epilepsy, 57.0% had onset of epilepsy in infancy, 25.8% have more than two clinical seizure forms, 62.5% require two or more anti-epileptic drug treatments, and 72.7% of the children have varying degrees of psychomotor development retardation. There are significant differences between ages of onset, neurodevelopmental levels and the presence of drug resistance in the genetic diagnostic yield (all p < 0.05). The 52 pathogenic/likely pathogenic SNVs involve 31 genes, with genes encoding ion channels having the largest number of mutations (30.8%). There were 16 cases of pathogenic/possibly pathogenic CNVs, among which the main proportions of CNVs were located in chromosome 15 and chromosome 16. Trio-WES is an essential tool for the genetic diagnosis of unexplained epilepsy, with a genetic diagnostic yield of up to 50.8%. Early genetic testing can provide an initiate appropriate therapies and accurate molecular diagnosis.

The value of hybrid genomes: Building two highly contiguous reference genome assemblies to advance Canis genomic studies.

Previous studies of canid population and evolutionary genetics have relied on high-quality domestic dog reference genomes that have been produced primarily for biomedical and trait mapping studies in dog breeds. However, the absence of highly contiguous genomes from other Canis species like the gray wolf and coyote, that represent additional distinct demographic histories, may bias inferences regarding interspecific genetic diversity and phylogenetic relationships. Here, we present single haplotype de novo genome assemblies for the gray wolf and coyote, generated by applying the trio-binning approach to long sequence reads generated from the genome of a female first-generation hybrid produced from a gray wolf and coyote mating. The assemblies were highly contiguous, with contig N50 sizes of 44.6 and 42.0 Mb for the wolf and coyote, respectively. Genome scaffolding and alignments between the two Canis assemblies and published dog reference genomes showed near complete collinearity, with one exception: a coyote-specific chromosome fission of chromosome 13 and fusion of the proximal portion of that chromosome with chromosome 8, retaining the Canis-typical haploid chromosome number of 2n = 78. We evaluated mapping quality for previous RADseq data from 334 canids and found nearly identical mapping quality and patterns among canid species and regional populations regardless of the genome used for alignment (dog, coyote, or gray wolf). These novel wolf and coyote genome reference assemblies will be important resources for proper and accurate inference of Canis demography, taxonomic evaluation, and conservation genetics.