@article {789, title = {Diagnostic yield and clinical impact of exome sequencing in early-onset scoliosis (EOS).}, journal = {J Med Genet}, volume = {58}, year = {2021}, month = {2021 Jan}, pages = {41-47}, abstract = {

BACKGROUND: Early-onset scoliosis (EOS), defined by an onset age of scoliosis less than 10 years, conveys significant health risk to affected children. Identification of the molecular aetiology underlying patients with EOS could provide valuable information for both clinical management and prenatal screening.

METHODS: In this study, we consecutively recruited a cohort of 447 Chinese patients with operative EOS. We performed exome sequencing (ES) screening on these individuals and their available family members (totaling 670 subjects). Another cohort of 13 patients with idiopathic early-onset scoliosis (IEOS) from the USA who underwent ES was also recruited.

RESULTS: After ES data processing and variant interpretation, we detected molecular diagnostic variants in 92 out of 447 (20.6\%) Chinese patients with EOS, including 8 patients with molecular confirmation of their clinical diagnosis and 84 patients with molecular diagnoses of previously unrecognised diseases underlying scoliosis. One out of 13 patients with IEOS from the US cohort was molecularly diagnosed. The age at presentation, the number of organ systems involved and the Cobb angle were the three top features predictive of a molecular diagnosis.

CONCLUSION: ES enabled the molecular diagnosis/classification of patients with EOS. Specific clinical features/feature pairs are able to indicate the likelihood of gaining a molecular diagnosis through ES.

}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2019-106823}, author = {Zhao, Sen and Zhang, Yuanqiang and Chen, Weisheng and Li, Weiyu and Wang, Shengru and Wang, Lianlei and Zhao, Yanxue and Lin, Mao and Ye, Yongyu and Lin, Jiachen and Zheng, Yu and Liu, Jiaqi and Zhao, Hengqiang and Yan, Zihui and Yang, Yongxin and Huang, Yingzhao and Lin, Guanfeng and Chen, Zefu and Zhang, Zhen and Liu, Sen and Jin, Lichao and Wang, Zhaoyang and Chen, Jingdan and Niu, Yuchen and Li, Xiaoxin and Wu, Yong and Wang, Yipeng and Du, Renqian and Gao, Na and Zhao, Hong and Yang, Ying and Liu, Ying and Tian, Ye and Li, Wenli and Zhao, Yu and Liu, Jia and Yu, Bin and Zhang, Na and Yu, Keyi and Yang, Xu and Li, Shugang and Xu, Yuan and Hu, Jianhua and Liu, Zhe and Shen, Jianxiong and Zhang, Shuyang and Su, Jianzhong and Khanshour, Anas M and Kidane, Yared H and Ramo, Brandon and Rios, Jonathan J and Liu, Pengfei and Sutton, V Reid and Posey, Jennifer E and Wu, Zhihong and Qiu, Guixing and Wise, Carol A and Zhang, Feng and Lupski, James R and Zhang, Jianguo and Wu, Nan} } @article {708, title = {Genetic and molecular mechanism for distinct clinical phenotypes conveyed by allelic truncating mutations implicated in FBN1.}, journal = {Mol Genet Genomic Med}, volume = {8}, year = {2020}, month = {2020 01}, pages = {e1023}, abstract = {

BACKGROUND: The molecular and genetic mechanisms by which different single nucleotide variant alleles in specific genes, or at the same genetic locus, cause distinct disease phenotypes often remain unclear. Allelic truncating mutations of FBN1 could cause either classical Marfan syndrome (MFS) or a more complicated phenotype associated with Marfanoid-progeroid-lipodystrophy syndrome (MPLS).

METHODS: We investigated a small cohort, encompassing two classical MFS and one MPLS subjects~from China, whose clinical presentation included scoliosis potentially requiring surgical intervention. Targeted next generation sequencing was performed on all the participants. We analyzed the molecular diagnosis, clinical features, and the potential molecular mechanism involved in the MPLS subject in our cohort.

RESULTS: We report a novel de novo FBN1 mutation for the first Chinese subject~with MPLS, a more complicated fibrillinopathy, and two subjects~with more classical MFS. We further predict that the MPLS truncating mutation, and others previously reported, is prone to escape the nonsense-mediated decay (NMD), while MFS mutations are predicted to be subjected to NMD. Also, the MPLS mutation occurs within the glucogenic hormone asprosin domain of FBN1. In vitro experiments showed that the single MPLS mutation p.Glu2759Cysfs*9 appears to perturb proper FBN1 protein aggregation as compared with the~classical MFS mutation p.Tyr2596Thrfs*86. Both mutations appear to upregulate SMAD2 phosphorylation in vitro.

CONCLUSION: We provide direct evidence that a dominant-negative interaction of FBN1 potentially explains the complex MPLS phenotypes through genetic and functional analysis. Our study expands the mutation spectrum of FBN1 and highlights the potential molecular mechanism for MPLS.

}, keywords = {Adolescent, Adult, Child, Female, Fibrillin-1, HEK293 Cells, Humans, Lipodystrophy, Marfan Syndrome, Mutation, Phenotype, Progeria, Protein Domains, Smad2 Protein}, issn = {2324-9269}, doi = {10.1002/mgg3.1023}, author = {Lin, Mao and Liu, Zhenlei and Liu, Gang and Zhao, Sen and Li, Chao and Chen, Weisheng and Coban Akdemir, Zeynep and Lin, Jiachen and Song, Xiaofei and Wang, Shengru and Xu, Qiming and Zhao, Yanxue and Wang, Lianlei and Zhang, Yuanqiang and Yan, Zihui and Liu, Sen and Liu, Jiaqi and Chen, Yixin and Zuo, Yuzhi and Yang, Xu and Sun, Tianshu and Yang, Xin-Zhuang and Niu, Yuchen and Li, Xiaoxin and You, Wesley and Qiu, Bintao and Ding, Chen and Liu, Pengfei and Zhang, Shuyang and Carvalho, Claudia M B and Posey, Jennifer E and Qiu, Guixing and Lupski, James R and Wu, Zhihong and Zhang, Jianguo and Wu, Nan} } @article {774, title = {TBX6 missense variants expand the mutational spectrum in a non-Mendelian inheritance disease.}, journal = {Hum Mutat}, volume = {41}, year = {2020}, month = {2020 01}, pages = {182-195}, abstract = {

Congenital scoliosis (CS) is a birth defect with variable clinical and anatomical manifestations due to spinal malformation. The genetic etiology underlying about 10\% of CS cases in the Chinese population is compound inheritance by which the gene dosage is reduced below that of haploinsufficiency. In this genetic model, the trait manifests as a result of the combined effect of a rare variant and common pathogenic variant allele at a locus. From exome sequencing (ES) data of 523 patients in Asia and two patients in Texas, we identified six TBX6 gene-disruptive variants from 11 unrelated CS patients via ES and in vitro functional testing. The in trans mild hypomorphic allele was identified in 10 of the 11 subjects; as anticipated these 10 shared a similar spinal deformity of hemivertebrae. The remaining case has a homozygous variant in TBX6 (c.418C>T) and presents a more severe spinal deformity phenotype. We found decreased transcriptional activity and abnormal cellular localization as the molecular mechanisms for TBX6 missense loss-of-function alleles. Expanding the mutational spectrum of TBX6 pathogenic alleles enabled an increased molecular diagnostic detection rate, provided further evidence for the gene dosage-dependent genetic model underlying CS, and refined clinical classification.

}, keywords = {Alleles, Cell Line, Female, Gene Expression, Genes, Reporter, Genetic Association Studies, Genetic Predisposition to Disease, Genotype, Haplotypes, Humans, Inheritance Patterns, Male, Models, Molecular, Molecular Diagnostic Techniques, Mutation, Missense, Phenotype, Protein Conformation, Radiography, Sequence Analysis, DNA, Spine, Structure-Activity Relationship, T-Box Domain Proteins, Whole Exome Sequencing}, issn = {1098-1004}, doi = {10.1002/humu.23907}, author = {Chen, Weisheng and Lin, Jiachen and Wang, Lianlei and Li, Xiaoxin and Zhao, Sen and Liu, Jiaqi and Akdemir, Zeynep C and Zhao, Yanxue and Du, Renqian and Ye, Yongyu and Song, Xiaofei and Zhang, Yuanqiang and Yan, Zihui and Yang, Xinzhuang and Lin, Mao and Shen, Jianxiong and Wang, Shengru and Gao, Na and Yang, Ying and Liu, Ying and Li, Wenli and Liu, Jia and Zhang, Na and Yang, Xu and Xu, Yuan and Zhang, Jianguo and Delgado, Mauricio R and Posey, Jennifer E and Qiu, Guixing and Rios, Jonathan J and Liu, Pengfei and Wise, Carol A and Zhang, Feng and Wu, Zhihong and Lupski, James R and Wu, Nan} } @article {570, title = {TBX6 compound inheritance leads to congenital vertebral malformations in humans and mice.}, journal = {Hum Mol Genet}, volume = {28}, year = {2019}, month = {2019 02 15}, pages = {539-547}, abstract = {

Congenital vertebral malformations (CVMs) are associated with human TBX6 compound inheritance that combines a rare null allele and a common hypomorphic allele at the TBX6 locus. Our previous in vitro evidence suggested that this compound inheritance resulted in a TBX6 gene dosage of less than haploinsufficiency (i.e. <50\%) as a potential mechanism of TBX6-associated CVMs. To further investigate this pathogenetic model, we ascertained and collected 108 Chinese CVM cases and found that 10 (9.3\%) of them carried TBX6 null mutations in combination with common hypomorphic variants at the second TBX6 allele. For in vivo functional verification and genetic analysis of TBX6 compound inheritance, we generated both null and hypomorphic mutations in mouse Tbx6 using the CRISPR-Cas9 method. These Tbx6 mutants are not identical to the patient variants at the DNA sequence level, but instead functionally mimic disease-associated TBX6 variants. Intriguingly, as anticipated by the compound inheritance model, a high penetrance of CVM phenotype was only observed in the mice with combined null and hypomorphic alleles of Tbx6. These findings are consistent with our experimental observations in humans and supported the dosage effect of TBX6 in CVM etiology. In conclusion, our findings in the newly collected human CVM subjects and Tbx6 mouse models consistently support the contention that TBX6 compound inheritance causes CVMs, potentially via a gene dosage-dependent mechanism. Furthermore, mouse Tbx6 mutants mimicking human CVM-associated variants will be useful models for further mechanistic investigations of CVM pathogenesis in the cases associated with TBX6.

}, keywords = {Adolescent, Alleles, Animals, Child, Child, Preschool, Congenital Abnormalities, CRISPR-Cas Systems, Disease Models, Animal, Female, Haploinsufficiency, Humans, Infant, Male, Mice, Mutation, Phenotype, Scoliosis, Spine, T-Box Domain Proteins}, issn = {1460-2083}, doi = {10.1093/hmg/ddy358}, author = {Yang, Nan and Wu, Nan and Zhang, Ling and Zhao, Yanxue and Liu, Jiaqi and Liang, Xiangyu and Ren, Xiaojun and Li, Weiyu and Chen, Weisheng and Dong, Shuangshuang and Zhao, Sen and Lin, Jiachen and Xiang, Hang and Xue, Huadan and Chen, Lu and Sun, Hao and Zhang, Jianguo and Shi, Jiangang and Zhang, Shuyang and Lu, Daru and Wu, Xiaohui and Jin, Li and Ding, Jiandong and Qiu, Guixing and Wu, Zhihong and Lupski, James R and Zhang, Feng} } @article {517, title = {Perturbations of BMP/TGF-β and VEGF/VEGFR signalling pathways in non-syndromic sporadic brain arteriovenous malformations (BAVM).}, journal = {J Med Genet}, volume = {55}, year = {2018}, month = {2018 Oct}, pages = {675-684}, abstract = {

BACKGROUND: Brain arteriovenous malformations (BAVM) represent a congenital anomaly of the cerebral vessels with a prevalence of 10-18/100 000. BAVM is the leading aetiology of intracranial haemorrhage in children. Our objective was to identify gene variants potentially contributing to disease and to better define the molecular aetiology underlying non-syndromic sporadic BAVM.

METHODS: We performed whole-exome trio sequencing of 100 unrelated families with a clinically uniform BAVM phenotype. Pathogenic variants were then studied in vivo using a transgenic zebrafish model.

RESULTS: We identified four pathogenic heterozygous variants in four patients, including one in the established BAVM-related gene, , and three damaging variants in novel candidate genes: , and , which we then functionally validated in zebrafish. In addition, eight likely pathogenic heterozygous variants (, and ) were identified in eight patients, and 16 patients carried one or more variants of uncertain significance. Potential oligogenic inheritance ( with , with and with ) was identified in three patients. Regulation of sma- and mad-related proteins (SMADs) (involved in bone morphogenic protein (BMP)/transforming growth factor beta (TGF-β) signalling) and vascular endothelial growth factor (VEGF)/vascular endotheliual growth factor recepter 2 (VEGFR2) binding and activity (affecting the VEGF signalling pathway) were the most significantly affected biological process involved in the pathogenesis of BAVM.

CONCLUSIONS: Our study highlights the specific role of BMP/TGF-β and VEGF/VEGFR signalling in the aetiology of BAVM and the efficiency of intensive parallel sequencing in the challenging context of genetically heterogeneous paradigm.

}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2017-105224}, author = {Wang, Kun and Zhao, Sen and Liu, Bowen and Zhang, Qianqian and Li, Yaqi and Liu, Jiaqi and Shen, Yan and Ding, Xinghuan and Lin, Jiachen and Wu, Yong and Yan, Zihui and Chen, Jia and Li, Xiaoxin and Song, Xiaofei and Niu, Yuchen and Liu, Jian and Chen, Weisheng and Ming, Yue and Du, Renqian and Chen, Cong and Long, Bo and Zhang, Yisen and Tong, Xiangjun and Zhang, Shuyang and Posey, Jennifer E and Zhang, Bo and Wu, Zhihong and Wythe, Joshua D and Liu, Pengfei and Lupski, James R and Yang, Xinjian and Wu, Nan} }