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, ENG, and three damaging variants in novel candidate genes: PITPNM3, SARS and LEMD3, which we then functionally validated in zebrafish. In addition, eight likely pathogenic heterozygous variants (TIMP3, SCUBE2, MAP4K4, CDH2, IL17RD, PREX2, ZFYVE16 and EGFR) were identified in eight patients, and 16 patients carried one or more variants of uncertain significance. Potential oligogenic inheritance (MAP4K4 with ENG, RASA1 with TIMP3 and SCUBE2 with ENG) 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.
- brain arteriovenous malformation (bavm)
- whole exome sequencing
- genetics heterogeneity
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KW and SZ contributed equally.
Contributors NW, XY and PL conceived of the project and designed the study. KW, QZ, XD, Jian L, YZ and XY enrolled the cohort. SeZ, BowL, YL, JiaqL, JiacL, WC, XS, XL, YN, BoL and JC conducted the experiments. ZB, YS, JW and XT provided technical support for zebrafish experiments. SeZ, KW, QZ, YW, PL and NW analysed the data. XS, YW and ZY conducted the bioinformatic analyses. RD, CC and YM assisted with data interpretation and revised the manuscript. ZW, JRL, JEP, BZ and ShuyangZ assisted with study organisation and manuscript revision. SeZ, JDW, NW, KW and PL wrote the manuscript.
Funding National Natural Science Foundation of China (81671139 and 81220108007 to XY, and 81501852 to NW), Beijing Nova Program (Z161100004916123 to NW), National Key Research and Development Plan of China (2016YFC1300800 and 2016YFC090150 to XY, 2016YFC0901501 to ShZ), 2016 Milstein Medical Asian American Partnership Foundation Fellowship Award in Translational Medicine (to NW), CAMS Initiative Fund for Medical Sciences (2016-I2M-3-003 to NW), Beijing Natural Science Foundation (7172175 to NW), Central Level Public Interest Program for Scientific Research Institute (2016ZX310177 to NW), PUMC Youth Fund & the Fundamental Research Funds for the Central Universities (3332016006 to NW), Distinguished Youth Foundation of Peking Union Medical College Hospital (JQ201506 to NW), the Beijing Nova Program Interdisciplinary Collaborative Project (xxjc201717 to NW), the American Heart Association (16GRNT31330023 to JW), the National Key Research and Development Program of China, Stem Cell and Translational Research (2016YFA0100500 to XT), the National Institute of Neurological Disorders and Stroke (NINDS R01N058529 to JRL), National Human Genome Research Institute/National Heart, Lung, and Blood Institute (NHGRI/NHLBI UM1 HG006542) and the National Human Genome Research Institute (NHGRI K08 HG008986 to JEP).
Competing interests JRL has stock ownership in 23andMe and Lasergen, is a paid consultant for Regeneron Pharmaceuticals and is a coinventor on multiple US and European patents related to molecular diagnostics for inherited neuropathies, eye diseases and bacterial genomic fingerprinting. The Department of Molecular and Human Genetics at Baylor College of Medicine derives revenue from the chromosomal microarray analysis and clinical exome sequencing offered in the Baylor Genetics Laboratory (http://bmgl.com).
Patient consent Obtained.
Ethics approval This study was approved by the ethics committee of Beijing Tiantan Hospital under KYSB2016-060. Zebrafish experiments were approved by the Institutional Animal Care and Use Committee of Peking University under reference LSC-ZhangB-1.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
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