Copy number variants in patients with short stature.
ABSTRACT: Height is a highly heritable and classic polygenic trait. Recent genome-wide association studies (GWAS) have revealed that at least 180 genetic variants influence adult height. However, these variants explain only about 10% of the phenotypic variation in height. Genetic analysis of short individuals can lead to the discovery of novel rare gene defects with a large effect on growth. In an effort to identify novel genes associated with short stature, genome-wide analysis for copy number variants (CNVs), using single-nucleotide polymorphism arrays, in 162 patients (149 families) with short stature was performed. Segregation analysis was performed if possible, and genes in CNVs were compared with information from GWAS, gene expression in rodents' growth plates and published information. CNVs were detected in 40 families. In six families, a known cause of short stature was found (SHOX deletion or duplication, IGF1R deletion), in two combined with a de novo potentially pathogenic CNV. Thirty-three families had one or more potentially pathogenic CNVs (n=40). In 24 of these families, segregation analysis could be performed, identifying three de novo CNVs and nine CNVs segregating with short stature. Four were located near loci associated with height in GWAS (ADAMTS17, TULP4, PRKG2/BMP3 and PAPPA). Besides six CNVs known to be causative for short stature, 40 CNVs with possible pathogenicity were identified. Segregation studies and bioinformatics analysis suggested various potential candidate genes.
Project description:BACKGROUND/AIMS:In addition to genome-wide association studies (GWAS), height-associated genes may be uncovered by studying individuals with extreme short or tall stature. METHODS:Genome-wide analysis for copy number variants (CNVs), using single nucleotide polymorphism (SNP) arrays, was performed in 49 index cases born small for gestational age with persistent short stature. Segregation analysis was performed, and genes in CNVs were compared with information from GWAS, gene expression in rodents' growth plates, and published information. RESULTS:CNVs were detected in 13 cases. In 5 children a known cause of short stature was found: UPD7, UPD14, a duplication of the SHOX enhancer region, an IGF1R deletion, and a 22q11.21 deletion. In the remaining 8 cases, potential pathogenic CNVs were detected, either de novo (n = 1), segregating (n = 2), or not segregating with short stature (n = 5). Bioinformatic analysis of the de novo and segregating CNVs suggested that HOXD4, AGPS, PDE11A, OSBPL6, PRKRA and PLEKHA3, and possibly DGKB and TNFRSF11B are potential candidate genes. A SERPINA7 or NRK defect may be associated with an X-linked form of short stature. CONCLUSION:SNP arrays detected 5 known causes of short stature with prenatal onset and suggested several potential candidate genes.
Project description:Human growth has an estimated heritability of about 80%-90%. Nevertheless, the underlying cause of shortness of stature remains unknown in the majority of individuals. Genome-wide association studies (GWAS) showed that both common single nucleotide polymorphisms and copy number variants (CNVs) contribute to height variation under a polygenic model, although explaining only a small fraction of overall genetic variability in the general population. Under the hypothesis that severe forms of growth retardation might also be caused by major gene effects, we searched for rare CNVs in 200 families, 92 sporadic and 108 familial, with idiopathic short stature compared to 820 control individuals. Although similar in number, patients had overall significantly larger CNVs (p-value<1×10(-7)). In a gene-based analysis of all non-polymorphic CNVs>50 kb for gene function, tissue expression, and murine knock-out phenotypes, we identified 10 duplications and 10 deletions ranging in size from 109 kb to 14 Mb, of which 7 were de novo (p<0.03) and 13 inherited from the likewise affected parent but absent in controls. Patients with these likely disease causing 20 CNVs were smaller than the remaining group (p<0.01). Eleven (55%) of these CNVs either overlapped with known microaberration syndromes associated with short stature or contained GWAS loci for height. Haploinsufficiency (HI) score and further expression profiling suggested dosage sensitivity of major growth-related genes at these loci. Overall 10% of patients carried a disease-causing CNV indicating that, like in neurodevelopmental disorders, rare CNVs are a frequent cause of severe growth retardation.
Project description:Idiopathic short stature (ISS) refers to short stature with no evident etiologies. The custom genome-wide microarray specifically designed to cover height-related genes may be helpful to detect copy number variations (CNVs) in ISS patients, which may be missed by the general microarray. The aim of the study was to validate the applicability of the custom microarray and to analyze CNVs in Chinese ISS children.Sixty non-polymorphic CNVs were identified in 119 ISS patients. There were 13 small CNVs with a size below 50 kb, accounting for 21.7 % of all the CNVs (13/60). Five pathogenic or possibly pathogenic CNVs were detected in five patients, including deletions at 22q11.21, duplications at 4q11-q13.1, 4q12 and Yp11.32-p11.2. Taking only the pathogenic variants into account, the diagnostic yield was 2.5 % (3/119). The TMEM165, POLR2B and PDGFRA genes were analyzed as candidate genes. A 15 kb deletion in the RASA2 gene was of interest for further investigation.This study showed that the custom microarray is applicable to detect CNVs in patients with short stature. Candidate genes and CNVs detected in ISS patients may be helpful for CNV analysis of short stature, especially in East Asian population.
Project description:Height is a heritable and highly heterogeneous trait. Short stature affects 3% of the population and in most cases is genetic in origin. After excluding known causes, 67% of affected individuals remain without diagnosis. To identify novel candidate genes for short stature, we performed exome sequencing in 254 unrelated families with short stature of unknown cause and identified variants in 63 candidate genes in 92 (36%) independent families. Based on systematic characterization of variants and functional analysis including expression in chondrocytes, we classified 13 genes as strong candidates. Whereas variants in at least two families were detected for all 13 candidates, two genes had variants in 6 (UBR4) and 8 (LAMA5) families, respectively. To facilitate their characterization, we established a clustered network of 1025 known growth and short stature genes, which yielded 29 significantly enriched clusters, including skeletal system development, appendage development, metabolic processes, and ciliopathy. Eleven of the candidate genes mapped to 21 of these clusters, including CPZ, EDEM3, FBRS, IFT81, KCND1, PLXNA3, RASA3, SLC7A8, UBR4, USP45, and ZFHX3. Fifty additional growth-related candidates we identified await confirmation in other affected families. Our study identifies Mendelian forms of growth retardation as an important component of idiopathic short stature.
Project description:Genome-Wide Association Studies (GWAS) in large human cohorts have identified thousands of loci associated with complex traits and diseases. For identifying the genes and gene-associated variants that underlie complex traits in livestock, especially where sample sizes are limiting, it may help to integrate the results of GWAS for equivalent traits in humans as prior information. In this study, we sought to investigate the usefulness of results from a GWAS on human height as prior information for identifying the genes and gene-associated variants that affect stature in cattle, using GWAS summary data on samples sizes of 700,000 and 58,265 for humans and cattle, respectively. Using Fisher's exact test, we observed a significant proportion of cattle stature-associated genes (30/77) that are also associated with human height (odds ratio = 5.1, p = 3.1e-10). Result of randomized sampling tests showed that cattle orthologs of human height-associated genes, hereafter referred to as candidate genes (C-genes), were more enriched for cattle stature GWAS signals than random samples of genes in the cattle genome (p = 0.01). Randomly sampled SNPs within the C-genes also tend to explain more genetic variance for cattle stature (up to 13.2%) than randomly sampled SNPs within random cattle genes (p = 0.09). The most significant SNPs from a cattle GWAS for stature within the C-genes did not explain more genetic variance for cattle stature than the most significant SNPs within random cattle genes (p = 0.87). Altogether, our findings support previous studies that suggest a similarity in the genetic regulation of height across mammalian species. However, with the availability of a powerful GWAS for stature that combined data from 8 cattle breeds, prior information from human-height GWAS does not seem to provide any additional benefit with respect to the identification of genes and gene-associated variants that affect stature in cattle.
Project description:Human height is a classic polygenic trait and currently available data explains only 10% of the phenotypic variation in height. Almost 60%-80% of the children coming to pediatric and endocrinology outpatient department for the evaluation of short stature are still labeled as idiopathic.The aim of this study is to identify various chromosomal alterations causing idiopathic short stature (ISS) and short stature with dysmorphic features not pertaining to known genetic syndromes.After exclusion of all nutritional, systemic, endocrine, and syndromic causes of short stature, 19 patients with height <2 standard deviation scores were subjected to chromosomal microarray (CMA) study using Affymetrix CytoScan 750K array and CMA Scanner 3000 platform.We identified total 61 copy-number variant (CNV) and polymorphs (33 gains, 11 loss, and 17 gain-mosaics) not described as normal variants in database of genomic variations. We identified SHOX haploinsufficiency as a cause of short stature in two patients, whereas one patient was gain-mosaic for SHOX. All three had normal conventional karyotype. One of these patients also had deletion of PAX3, which could be the cause of both short stature and associated mild intellectual impairment in this patient. We also found a long noncoding RNA, namely, KIAA0125 and a pseudogene ADAM6 in 18 out of our 19 patients which might have a regulatory role.This study shows that CMA is a very promising tool for the identification of pathogenic CNVs in patients with ISS. It can also help to identify novel genes controlling height and can open up new insight into pathophysiologic mechanisms underlying ISS, and thus may help to unfold new therapeutic targets for treatment of this condition. The association of CNV having genes for long noncoding RNAs, such as KIAA0125 and pseudogene such as ADAM6 with ISS suggest that they may play a role in controlling the expression of height-related genes and it needs further investigations.
Project description:Height is a model polygenic trait that is highly heritable. Genome-wide association studies have identified hundreds of single-nucleotide polymorphisms associated with stature, but the role of structural variation in determining height is largely unknown. We performed a genome-wide association study of copy-number variation and stature in a clinical cohort of children who had undergone comparative genomic hybridization (CGH) microarray analysis for clinical indications. We found that subjects with short stature had a greater global burden of copy-number variants (CNVs) and a greater average CNV length than did controls (p < 0.002). These associations were present for lower-frequency (<5%) and rare (<1%) deletions, but there were no significant associations seen for duplications. Known gene-deletion syndromes did not account for our findings, and we saw no significant associations with tall stature. We then extended our findings into a population-based cohort and found that, in agreement with the clinical cohort study, an increased burden of lower-frequency deletions was associated with shorter stature (p = 0.015). Our results suggest that in individuals undergoing copy-number analysis for clinical indications, short stature increases the odds that a low-frequency deletion will be found. Additionally, copy-number variation might contribute to genetic variation in stature in the general population.
Project description:OBJECTIVE:The authors used a genome-wide association study (GWAS) of multiply affected families to investigate the association of schizophrenia to common single-nucleotide polymorphisms (SNPs) and rare copy number variants (CNVs). METHOD:The family sample included 2,461 individuals from 631 pedigrees (581 in the primary European-ancestry analyses). Association was tested for single SNPs and genetic pathways. Polygenic scores based on family study results were used to predict case-control status in the Schizophrenia Psychiatric GWAS Consortium (PGC) data set, and consistency of direction of effect with the family study was determined for top SNPs in the PGC GWAS analysis. Within-family segregation was examined for schizophrenia-associated rare CNVs. RESULTS:No genome-wide significant associations were observed for single SNPs or for pathways. PGC case and control subjects had significantly different genome-wide polygenic scores (computed by weighting their genotypes by log-odds ratios from the family study) (best p=10(-17), explaining 0.4% of the variance). Family study and PGC analyses had consistent directions for 37 of the 58 independent best PGC SNPs (p=0.024). The overall frequency of CNVs in regions with reported associations with schizophrenia (chromosomes 1q21.1, 15q13.3, 16p11.2, and 22q11.2 and the neurexin-1 gene [NRXN1]) was similar to previous case-control studies. NRXN1 deletions and 16p11.2 duplications (both of which were transmitted from parents) and 22q11.2 deletions (de novo in four cases) did not segregate with schizophrenia in families. CONCLUSIONS:Many common SNPs are likely to contribute to schizophrenia risk, with substantial overlap in genetic risk factors between multiply affected families and cases in large case-control studies. Our findings are consistent with a role for specific CNVs in disease pathogenesis, but the partial segregation of some CNVs with schizophrenia suggests that researchers should exercise caution in using them for predictive genetic testing until their effects in diverse populations have been fully studied.
Project description:Abstract Background: Short stature is a common pediatric disorder, affecting 3% of the population; however, the identification of its cause is limited by its largely variable clinical presentation and genetic heterogeneity. Identification of novel genetic causes of short stature is of great importance to customize the therapeutic approach of this entity. The especial AT-rich sequence binding protein1 gene (SATB1) encodes a chromatin organizer with important roles in cell growth and immunosuppression. SATB1 is highly expressed in the pituitary gland, where it regulates the differentiation of PIT1 positive cells. Indeed, the conditional knockout of Satb1 in the mouse pituitary decreases growth hormone expression, leading to reduced growth. Aim: To investigate the putative role of SATB1 in growth in a cohort of individuals with short stature and in a zebrafish knockout (KO) model. Methods: We obtained germline DNA samples from a cohort of 287 Brazilian patients diagnosed with short stature (height <2 SDS for age and sex), including 52 patients small for gestational age (SGA), 5 cases with growth hormone deficiency (GHD), 10 cases with syndromic short stature and 220 cases with idiopathic short stature. All cases were screened for SATB1 copy number variations (CNVs) using droplet digital PCR, and 190 cases were screened for mutations via Sanger sequencing. In silico predictions were retrieved from the Varsome browser. All variants were annotated to RefSeq NM_002971.5. Using CRISPR-Cas9, we generated two lines of zebrafish satb1 bearing frameshift mutations; both lines were crossed to obtain full KOs. Growth was monitored from 3 to 12 weeks post-fertilization (wpf) and expression of pituitary hormones was analyzed at 6 wpf by quantitative PCR. Results: No variants predicted as damaging were found in the short stature cohort. Nevertheless, variants of uncertain significance (VUS, mostly intronic) were found in 11% of our cohort, in which 57% of the individuals that carry a VUS presented familial short stature while 43% were non-familial. Interestingly, the variant c.515+112G>A was identified in 3/33 (9.1%) of SGA patients, but only in 2/143 (1.4%) of ISS patients. No CNVs were observed. In the zebrafish model, satb1 knockout led to significantly smaller size at 3 wpf, compared with heterozygous and wild type controls (median standard length: 6.6, 7.4, and 7.8 cm, and mean weight: 2.7, 4.3, and 4.6 mg, respectively, P<0.05 for all comparisons). At 6 wpf, we identified a trend for lower gh1 expression in the KOs vs. heterozygous zebrafish (relative quantification: 0.68 vs. 1.79, P=0.06). Conclusion: Our results support a role for SATB1 in regulating growth hormone production across species. Although loss of SATB1 function could theoretically lead to growth hormone deficiency in humans, defects in this gene do not seem to play a crucial role in the height of individuals with short stature.
Project description:Human height can be described as a classical and inherited trait model. Genome-wide association studies (GWAS) have revealed susceptible loci and provided insights into the polygenic nature of human height. Familial short stature (FSS) represents a suitable trait for investigating short stature genetics because disease associations with short stature have been ruled out in this case. In addition, FSS is caused only by genetically inherited factors. In this study, we explored the correlations of FSS risk with the genetic loci associated with human height in previous GWAS, alone and cumulatively. We systematically evaluated 34 known human height single nucleotide polymorphisms (SNPs) in relation to FSS in the additive model (p?<?0.00005). A cumulative effect was observed: the odds ratios gradually increased with increasing genetic risk score quartiles (p?<?0.001; Cochran-Armitage trend test). Six affected genes-ZBTB38, ZNF638, LCORL, CABLES1, CDK10, and TSEN15-are located in the nucleus and have been implicated in embryonic, organismal, and tissue development. In conclusion, our study suggests that 13 human height GWAS-identified SNPs are associated with FSS risk both alone and cumulatively.