Project description:The identification of the genetic risk factors in patients with isolated cleft palate by whole genome sequencing analysis. Pathogenic or likely pathogenic variants were discovered in genes associated with CP (TBX22, COL2A1, FBN1, PCGF2, and KMT2D) in five patients; hence, rare disease variants were identified in 17% of patients with non-syndromic isolated CP. Our results are relevant to routine genetic counselling practice and genetic testing recommendations.
Project description:Autism affects males four times more often than females, yet the basis of this sex bias remains unclear. One hypothesis is that hypomorphic variants in X-linked genes—genes where loss-of-function alleles cause syndromic neurodevelopmental disorders (NDDs) predominantly in females—produce milder, non-syndromic phenotypes in hemizygous males. We tested this by investigating cis-regulatory elements (CREs) of MECP2, a dosage-sensitive X-linked gene. Using a massively parallel reporter assay in human neurons, we mapped transcription factor binding sites within MECP2 CREs and tested autism-associated variants for functional impact. We identified two noncoding variants that change CRE activity, each with a male-biased phenotype. One of these, a promoter variant, disrupts NFY binding and reduces MECP2 expression by ~30%, a magnitude that produces autism-like phenotypes in mice. These findings suggest noncoding MECP2 variants can cause non-syndromic, male-biased autism, and provide a framework for uncovering regulatory variants in other X-linked NDD genes that may contribute to autism’s missing heritability.
Project description:Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well-established that both common and rare sequence variants contribute to the formation of CL/P, however, the contribution of copy number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed, however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our case cohort compared to controls, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR/Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.
Project description:Cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex, heterogeneous etiology. It is well-established that both common and rare sequence variants contribute to the formation of CL/P, however, the contribution of copy number variants (CNVs) to cleft formation remains relatively understudied. To fill this knowledge gap, we conducted a large-scale comparative analysis of genome-wide CNV profiles of 869 individuals from the Philippines and 233 individuals of European ancestry with CL/P with three primary goals: first, to evaluate whether differences in CNV number, amount of genomic content, or amount of coding genomic content existed within clefting subtypes; second, to assess whether CNVs in our cohort overlapped with known Mendelian clefting loci; and third, to identify unestablished Mendelian clefting genes. Significant differences in CNVs across cleft types or in individuals with non-syndromic versus syndromic clefts were not observed, however, several CNVs in our cohort overlapped with known syndromic and non-syndromic Mendelian clefting loci. Moreover, employing a filtering strategy relying on population genetics data that rare variants are on the whole more deleterious than common variants, we identify several CNV-associated gene losses likely driving non-syndromic clefting phenotypes. By prioritizing genes deleted at a rare frequency across multiple individuals with clefts yet enriched in our case cohort compared to controls, we identify COBLL1, RIC1, and ARHGEF38 as clefting genes. CRISPR/Cas9 mutagenesis of these genes in Xenopus laevis and Danio rerio yielded craniofacial dysmorphologies, including clefts analogous to those seen in human clefting disorders.
Project description:A 640kb non-coding interval at 8q24 has been associated with an increased risk of non-syndromic cleft lip and palate (CLP) in humans, but the genes and pathways involved in this genetic susceptibility have remained elusive. With a large series of rearrangements engineered over the syntenic mouse region, we showed that this interval contains very remote cis-acting enhancers that control c-myc expression in the developing face. Deletion of this interval led to mild alteration of facial morphologies in mice and, sporadically, to CLP. At a molecular level, we identified mis-expression of several downstream genes, highlighting a combined impact on cranio-facial developmental network and general metabolic capacity. This dual molecular etiology may account for the prominent role to the 8q24 region in human facial dysmorphologies. ChIP-seq and transcriptomics analysis in wt or/and mutant mice
Project description:A large portion of common variant loci associated with genetic risk for schizophrenia reside within non-coding sequence of unknown function. Here, we demonstrate promoter and enhancer enrichment in schizophrenia variants associated with expression quantitative trait loci (eQTL). The enrichment is greater when functional annotations derived from human brain are used relative to peripheral tissues. Regulatory trait concordance analysis ranked genes within schizophrenia genome-wide significant loci, based on co-localization of a risk SNP, eQTL and regulatory element sequence. These include physical interactions of non-contiguous gene-proximal and distal elements bypassing the linear genome, which was verified in prefrontal cortex and human induced pluripotent stem cell derived neurons for the L-type calcium channel (CACNA1C) risk locus. Our findings point to a functional link between schizophrenia-associated non-coding SNPs and 3-dimensional genome architecture associated with chromosomal loopings and transcriptional regulation in the brain. Examination of H3K4me3 histone modifications in 3 samples.
Project description:Genome-wide association studies (GWAS) have boosted our knowledge of genetic risk variants in autoimmune diseases (AIDs). Most of the risk variants are located within or near genes with immunological functions, and the majority is found to be non-coding, pointing towards a regulatory role. We have performed a cis expression quantitative trait locus (eQTL) screen to investigate whether single nucleotide polymorphisms (SNPs) associated with AIDs influence gene expression in thymus. Genotyping was performed using the Immunochip and 353 AID associated SNPs were tested against expression of surrounding genes (+/- 1 Mb) from human thymic tissue (N=42). We identified eight genes where the expression was associated with AID risk SNPs at a study-wide level of significance (P < 2.57x10-5). Five genes (FCRL3, RNASET2, C2orf74, SIRPG and SYS1) displayed cis eQTL signals also in other tissues, while for two loci (NPIPB8 and LOC388814), the eQTL signal appear to be thymus-specific. Since many AID risk variants from GWAS have been subsequently fine-mapped in recent Immunochip projects, we explored the overlap between these novel AID risk variants and the thymic eQTL regions. Moreover, we examined the functional annotation of the seven expression altering SNPs (eSNPs). Our study reveals autoimmune risk variants that act as eQTLs in thymus. We have highlighted functional variants within these genetic regions that potentially can represent causal autoimmune risk variants. Total RNA from 42 human thymic samples were obtained from children undergoing cardiac surgery.
Project description:Various studies have established the role of genetics in the development of type 2 diabetes mellitus (T2DM) across population groups with a reported heritability of 30–70%. These studies highlight the effect of interethnic variability in genetic susceptibility and risk for complications of T2DM. The underrepresentation of Filipinos in current global databases have prompted the goal to identify variants associated with the risk of T2DM among the population. Since the validation of variants associated with one population seems suboptimal if applied to another population, designing a specific set of genetic variants for a particular population poses a challenge. Microarray techniques were used on extracted DNA from whole blood samples using customized microarray beadchips with selected variants from various genome repositories. Customization included candidates from both coding and non-coding regions (e.g. intergenic and intronic SNPs) with statistical evidence of associated to T2DM, its complications, treatment, diagnosis and other related conditions. Incorporation of clinical data from participants can then narrow the significant variants to the population and identify which can be valuable for developing genetic risk prediction models relevant to preventing and diagnosing the disease among Filipinos.
Project description:Various studies have established the role of genetics in the development of type 2 diabetes mellitus (T2DM) across population groups with a reported heritability of 30–70%. These studies highlight the effect of interethnic variability in genetic susceptibility and risk for complications of T2DM. The underrepresentation of Filipinos in current global databases have prompted the goal to identify variants associated with the risk of T2DM among the population. Since the validation of variants associated with one population seems suboptimal if applied to another population, designing a specific set of genetic variants for a particular population poses a challenge. Microarray techniques were used on extracted DNA from whole blood samples using customized microarray beadchips with selected variants from various genome repositories. Customization included candidates from both coding and non-coding regions (e.g. intergenic and intronic SNPs) with statistical evidence of associated to T2DM, its complications, treatment, diagnosis and other related conditions. Incorporation of clinical data from participants can then narrow the significant variants to the population and identify which can be valuable for developing genetic risk prediction models relevant to preventing and diagnosing the disease among Filipinos.