scholarly journals A Novel Homozygous Missense Mutation in the Zinc Finger DNA Binding Domain of GLI1 Causes Recessive Post-Axial Polydactyly

2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Umair ◽  
Farooq Ahmad ◽  
Saeed Ahmad ◽  
Qamre Alam ◽  
Mohd Rehan ◽  
...  

Background: Polydactyly is a prevalent digit abnormality characterized by having extra digits/toes. Mutations in eleven known genes have been associated to cause nonsyndromic polydactyly: GLI3, GLI1, ZRS regulating LMBR1, IQCE, ZNF141, PITX1, MIPOL1, FAM92A, STKLD1, KIAA0825, and DACH1.Method: A single affected family member (IV-4) was subjected to whole-exome sequencing (WES) to identify the causal gene. Bi-directional Sanger sequencing was performed to segregate the identified variant within the family. In silico analysis was performed to investigate the effect of the variant on DNA binding properties.Results: whole-exome sequencing identified a bi-allelic missense variant (c.1010C > T; p. Ser337Leu) in exon nine of GLI1 gene located on chromosome 12q13.3. With the use of Sanger sequencing, the identified variant segregated perfectly with the disease phenotype. Furthermore, in silico analysis of this DNA binding protein revealed that the variant weakened the DNA binding interaction, resulting in indecorous GLI1 function.Conclusion: Herein, we report a novel variant in GLI1 gene, causing autosomal recessive post-axial polydactyly type A (PAPA) type 8. This confirms the critical role of GLI1 in digit development and might help in genotype–phenotype correlation in the future.

2021 ◽  
Author(s):  
Rubab Raza ◽  
Raul Jimenez-Heredia ◽  
Muhammad Zeeshan Anwar ◽  
Asmat Ullah ◽  
Ayisha Zia ◽  
...  

Abstract Purpose Systemic auto-inflammatory diseases are a diverse group of heterogeneous disorders resulting in development of the systemic inflammation in absence of the inflammatory induction. Sequence variants in the OTULIN gene, which disrupts its ubiquitination activity lead to auto-inflammation, panniculitis, and dermatosis syndrome. To date, only few disease-causing variants in the OTULIN have been reported.In the study, presented here, sequence analysis of the OTULIN gene in a patient, exhibiting features of OTULIN-related auto-inflammatory syndrome (ORAS), revealed a novel disease-causing missense variant p.(Thr312Met). Further, effect of the variant on structure and function of the OTULIN protein has been examined using in silico OTULINWT and OTULINT312M. Methods Cells, collected from the patient blood, were examined by flow cytometry. Search for the disease-causing variants was carried out using exome followed by Sanger sequencing. Effect of the sequence variant on structure of the mutated protein was studied using in-silico analyses. Results Flow cytometry analysis revealed slightly reduced number of lymphocytes, marked leukocytosis, and mildly increased levels of IgG. Whole exome sequencing coupled with Sanger sequencing revealed a homozygous missense variant [c.935C>T; p.(Thr312Met)] in the OTULIN gene. In-silico analyses revealed that the missense variant reduces OTULIN’s expression and promotes accumulation of LUBAC-linked UB chains leading to auto-inflammation.Conclusion Taken together, OTULIN may act as a novel therapeutic target for the development of immunomodulatory drugs that may potentially increase or stabilize their expression. Targeting more components of the Ub-proteasome pathway may provide new opportunities for therapeutic exploitation and drug discovery.


2017 ◽  
Vol 176 (5) ◽  
pp. K9-K14 ◽  
Author(s):  
Sandrine Caburet ◽  
Ronit Beck Fruchter ◽  
Bérangère Legois ◽  
Marc Fellous ◽  
Stavit Shalev ◽  
...  

Context PCOS is a heterogeneous condition characterized by hyperandrogenism and chronic anovulation and affects about 10% of women. Its etiology is poorly known, but a dysregulation of gonadotropin secretion is one of its hallmarks. Objective As the etiology of PCOS is unclear, we have performed a genome-wide analysis of a consanguineous family with three sisters diagnosed with PCOS. Methods Whole-exome sequencing and Sanger sequencing confirmation. Results Whole-exome sequencing allowed the detection of the missense variant rs104893836 located in the first coding exon of the GNRHR gene and leading to the p.Gln106Arg (p.Q106R) substitution. Sanger sequencing of all available individuals of the family confirmed that the variant was homozygous in the three affected sisters and heterozygous in both parents. Conclusions This is the first description of a GNRHR gene mutation in patients diagnosed with PCOS. Although we do not exclude a possible interaction of the identified variant with the genetic background and/or the environment, our result suggests that genetic alterations in the hypothalamo–pituitary axis may play role in the pathogenesis of PCOS.


2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Hao Geng ◽  
Dongdong Tang ◽  
Chuan Xu ◽  
Xiaojin He ◽  
Zhiguo Zhang

Background. Split-hand/foot malformation (SHFM) is a severe congenital disability mainly characterized by the absence or hypoplasia of the central ray of the hand/foot. To date, several candidate genes associated with SHFM have been identified, including TP63, DLX5, DLX6, FGFR1, and WNT10B. Herein, we report a novel variant of TP63 heterozygously present in affected members of a family with SHFM. Methods. This study investigated a Chinese family, in which the proband and his son suffered from SHFM. The peripheral blood sample of the proband was used to perform whole-exome sequencing (WES) to explore the possible genetic causes of this disease. Postsequencing bioinformatic analyses and Sanger sequencing were conducted to verify the identified variants and parental origins on all family members in the pedigree. Results. By postsequencing bioinformatic analyses and Sanger sequencing, we identified a novel missense variant (NM_003722.4:c.948G>A; p.Met316Ile) of TP63 in this family that results in a substitution of methionine with isoleucine, which is probably associated with the occurrence of SHFM. Conclusion. A novel missense variant (NM_003722.4:c.948G>A; p.Met316Ile) of TP63 in SHFM was thus identified, which may enlarge the spectrum of known TP63 variants and also provide new approaches for genetic counselling of families with SHFM.


2017 ◽  
Vol 3 (4) ◽  
pp. e162 ◽  
Author(s):  
Nathan McNeill ◽  
Alessia Nasca ◽  
Aurelio Reyes ◽  
Benjamin Lemoine ◽  
Brandi Cantarel ◽  
...  

Objective:To investigate the genetic etiology of a patient diagnosed with leukoencephalopathy, brain calcifications, and cysts (LCC).Methods:Whole-exome sequencing was performed on a patient with LCC and his unaffected family members. The variants were subject to in silico and in vitro functional testing to determine pathogenicity.Results:Whole-exome sequencing uncovered compound heterozygous mutations in EARS2, c.328G>A (p.G110S), and c.1045G>A (p.E349K). This gene has previously been implicated in the autosomal recessive leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL). The p.G110S mutation has been found in multiple patients with LTBL. In silico analysis supported pathogenicity in the second variant. In vitro functional testing showed a significant mitochondrial dysfunction demonstrated by an ∼11% decrease in the oxygen consumption rate and ∼43% decrease in the maximum respiratory rate in the patient's skin fibroblasts compared with the control. EARS2 protein levels were reduced to 30% of normal controls in the patient's fibroblasts. These deficiencies were corrected by the expression of the wild-type EARS2 protein. However, a further unrelated genetic investigation of our patient revealed the presence of biallelic variants in a small nucleolar RNA (SNORD118) responsible for LCC.Conclusions:Here, we report seemingly pathogenic EARS2 mutations in a single patient with LCC with no biochemical or neuroimaging presentations of LTBL. This patient illustrates that variants with demonstrated impact on protein function should not necessarily be considered clinically relevant.ClinicalTrials.gov identifier:NCT00001671.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yu Xu ◽  
Yong-Biao Zhang ◽  
Li-Jun Liang ◽  
Jia-Li Tian ◽  
Jin-Ming Lin ◽  
...  

Abstract Background Hereditary hemorrhagic telangiectasia (HHT) is a disease characterized by arteriovenous malformations in the skin and mucous membranes. We enrolled a large pedigree comprising 32 living members, and screened for mutations responsible for HHT. Methods We performed whole-exome sequencing to identify novel mutations in the pedigree after excluding three previously reported HHT-related genes using Sanger sequencing. We then performed in silico functional analysis of candidate mutations that were obtained using a variant filtering strategy to identify mutations responsible for HHT. Results After screening the HHT-related genes, activin A receptor-like type 1 (ACVRL1), endoglin (ENG), and SMAD family member 4 (SMAD4), we did not detect any co-segregated mutations in this pedigree. Whole-exome sequencing analysis of 7 members and Sanger sequencing analysis of 16 additional members identified a mutation (c.784A > G) in the NSF attachment protein gamma (NAPG) gene that co-segregated with the disease. Functional prediction showed that the mutation was deleterious and might change the conformational stability of the NAPG protein. Conclusions NAPG c.784A > G may potentially lead to HHT. These results expand the current understanding of the genetic contributions to HHT pathogenesis.


Author(s):  
Bixia Zheng ◽  
Steve Seltzsam ◽  
Chunyan Wang ◽  
Luca Schierbaum ◽  
Sophia Schneider ◽  
...  

Abstract Background Congenital anomalies of the kidneys and urinary tract (CAKUT) constitute the most common cause of chronic kidney disease in the first three decades of life. Variants in four Forkhead box (FOX) transcription factors have been associated with CAKUT. We hypothesized that other FOX genes, if highly expressed in developing kidney, may also represent monogenic causes of CAKUT. Methods We here performed whole exome sequencing (WES) in 541 families with CAKUT and generated 4 lists of CAKUT candidate genes: A) 36 FOX genes showing high expression during renal development, B) 4 FOX genes known to cause CAKUT to validate list A; C) 80 genes that we identified as unique potential novel CAKUT candidate genes when performing WES in 541 CAKUT families, and D) 175 genes identified from WES as multiple potential novel CAKUT candidate genes. Results To prioritize potential novel CAKUT candidates in FOX gene family, we overlapped 36 FOX genes (list A) with list C and D of WES-derived CAKUT candidates. Intersection with list C, identified a de novo FOXL2 in-frame deletion in a patient with eyelid abnormalities and ureteropelvic junction obstruction, and a homozygous FOXA2 missense variant in a patient with horseshoe kidney. Intersection with list D, identified a heterozygous FOXA3 missense variant in a CAKUT family with multiple affected individuals. Conclusion We hereby identified FOXL2, FOXA2 and FOXA3 as novel monogenic candidate genes of CAKUT, supporting the utility of a paralog-based approach to discover mutated genes associated with human disease.


2018 ◽  
Author(s):  
Jose Velilla ◽  
Michael Mario Marchetti ◽  
Agnes Toth-Petroczy ◽  
Claire Grosgogeat ◽  
Alexis H Bennett ◽  
...  

AbstractObjectiveThe objective of this study is to identify the genetic cause of disease in a congenital form of congenital spinal muscular atrophy and arthrogryposis (CSMAA).MethodsA 2-year-old boy was diagnosed with arthrogryposis multiplex congenita, severe skeletal abnormalities, torticollis, vocal cord paralysis and diminished lower limb movement. Whole exome sequencing was performed on the proband and family members. In silico modeling of protein structure and heterologous protein expression and cytotoxicity assays were performed to validate pathogenicity of the identified variant.ResultsWhole exome sequencing revealed a homozygous mutation in the TRPV4 gene (c.281C>T; p.S94L). The identification of a recessive mutation in TRPV4 extends the spectrum of mutations in recessive forms of the TRPV4-associated disease. p.S94L and other previously identified TRPV4 variants in different protein domains were compared in structural modeling and functional studies. In silico structural modeling suggests that the p.S94L mutation is in the disordered N-terminal region proximal to important regulatory binding sites for phosphoinositides and for PACSIN3, which could lead to alterations in trafficking and/or channel sensitivity. Functional studies by western blot and immunohistochemical analysis show that p.S94L reduces TRPV4 protein stability because of increased cytotoxicity and therefore involves a gain-of-function mechanism.ConclusionThis study identifies a novel homozygous mutation in TRPV4 as a cause of the recessive form of congenital spinal muscular atrophy and arthrogryposis.


Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Changwei Li ◽  
Michael Francis ◽  
Adrianna Westbrook ◽  
Ruiyuan Zhang ◽  
Ye Shen ◽  
...  

Introduction: Most genetic variants for chronic kidney disease (CKD) have been identified in non-coding regions, with functional roles that are difficult to interpret. Hypothesis: A whole exome sequencing study focusing on coding variants will reveal novel mechanisms of kidney function and CKD. Methods: We performed whole exome sequencing analyses of cystatin C among 29,789 UK Biobank (UKB) participants with further confirmation among 4,297 white and 607 African American participants of the Health and Retirement Study (HRS). Conditional analyses for loci achieving exome-wide significance ( P <3.5х10 -7 ) were conducted in UKB using both the exome (n=29,789) and imputed GWAS data (n=295,122). Genomic findings were tested for relevance to baseline estimated glomerular filtration rate (eGFR) and stringently adjudicated CKD progression events among participants of the Chronic Renal Insufficiency Cohort (CRIC) by race and smoking status, using a base model and a full model ( Table ). Results: We identified a common missense variant, CST9 rs2983640, in a previously reported locus ( CST3 intron rs13038305), of which the minor G allele was associated with lower serum cystatin C level (UKB: beta=-0.03 mg/L, P =7.64х10 -92 ; HRS whites: beta=-0.05 mg/L, P =4.71х10 -6 ; HRS African Americans: beta=-0.03 mg/L, P =0.64; and multi-ethnic meta-analysis beta=-0.03 mg/L, P =2.46х10 -91 ). After controlling for the CST3 variant, the G allele was associated with higher cystatin C level (UKB exome: beta=0.003 mg/L, P =0.04; UKB GWAS: beta=0.003 mg/L, P =1.47х10 -10 ). Similar associations were identified in white CRIC participants (direct effect: beta=-0.05 mg/L, P =0.005; conditional effect: beta=0.004 mg/L, P =0.86). The CST9 rs2983640 G allele was associated with lower baseline eGFR (base model beta=-0.33 ml/min/1.73 m 2 , P =1.98х10 -6 ) and higher hazard of developing CKD progression independent of the reported CST3 variant ( Table ). Conclusions: We identified a novel missense variant influencing cystatin C level and CKD progression.


2020 ◽  
Author(s):  
Pengfei Liang ◽  
Fengping Chen ◽  
Shujuan Wang ◽  
Qiong Li ◽  
Wei Li ◽  
...  

Abstract Background: Hereditary non-syndromic hearing loss (NSHL) has a high genetic heterogeneity with >152 genes identified as associated molecular causes. The present study aimed to detect the possible damaging variants of the deaf probands from six unrelated Chinese families.Methods: After excluding the mutations in the most common genes, GJB2 and SLC26A4, 12 probands with prelingual deafness and autosomal recessive inheritance were evaluated by whole-exome sequencing (WES). All the candidate variants were verified by Sanger sequencing in all patients and their parents.Results: Biallelic mutations were identified in all deaf patients. Among these six families, 10 potentially causative mutations, including 3 reported and 7 novel mutations, in 3 different deafness-associated autosomal recessive (DFNB) genes (MYO15A, COL11A2, and CDH23) were identified. The mutations in MYO15A were frequent with 7/10 candidate variants. Sanger sequencing confirmed that these mutations segregated with the hearing loss of each family.Conclusions: Next-generation sequencing (NGS) approach becomes more cost-effective and efficient when analyzing large-scale genes compared to the conventional polymerase chain reaction-based Sanger sequencing, which is often used to screen common deafness-related genes. The current findings further extend the mutation spectrum of hearing loss in the Chinese population, which has a positive significance for genetic counseling.


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