title: Rare novel variants in the ZIC3 gene cause X-linked heterotaxy.
abstract: Variants in the ZIC3 gene are rare, but have demonstrated their profound clinical significance in X-linked heterotaxy, affecting in particular male patients with abnormal arrangement of thoracic and visceral organs. Several reports have shown relevance of ZIC3 gene variants in both familial and sporadic cases and with a predominance of mutations detected in zinc-finger domains. No studies so far have assessed the functional consequences of ZIC3 variants in an in vivo model organism. A study population of 348 patients collected over more than 10 years with a large variety of congenital heart disease including heterotaxy was screened for variants in the ZIC3 gene. Functional effects of three variants were assessed both in vitro and in vivo in the zebrafish. We identified six novel pathogenic variants (1,7%), all in either male patients with heterotaxy (n=5) or a female patient with multiple male deaths due to heterotaxy in the family (n=1). All variants were located within the zinc-finger domains or leading to a truncation before these domains. Truncating variants showed abnormal trafficking of mutated ZIC3 proteins, whereas the missense variant showed normal trafficking. Overexpression of wild-type and mutated ZIC protein in zebrafish showed full non-functionality of the two frame-shift variants and partial activity of the missense variant compared with wild-type, further underscoring the pathogenic character of these variants. Concluding, we greatly expanded the number of causative variants in ZIC3 and delineated the functional effects of three variants using in vitro and in vivo model systems.
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.|School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Aimee D C
authors.initials: AD
authors.lastname: Paulussen
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Anja
authors.initials: A
authors.lastname: Steyls
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Jo
authors.initials: J
authors.lastname: Vanoevelen
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.|School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Florence Hj
authors.initials: FH
authors.lastname: van Tienen
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Ingrid P C
authors.initials: IP
authors.lastname: Krapels
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Godelieve Rf
authors.initials: GR
authors.lastname: Claes
authors.affiliation: Cardiac Development and Genetics, Hubrecht Institute-KNAW and University Medical Centre Utrecht, The Netherlands.
authors.forename: Sonja
authors.initials: S
authors.lastname: Chocron
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Crool
authors.initials: C
authors.lastname: Velter
authors.affiliation: Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Gita M
authors.initials: GM
authors.lastname: Tan-Sindhunata
authors.affiliation: Department of Clinical Genetics, Office for Medical Services, Division of Laboratory Medicine, Lund, Sweden.
authors.forename: Catarina
authors.initials: C
authors.lastname: Lundin
authors.affiliation: Department of Clinical Genetics and Cytogenetics, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Valenzuela
authors.affiliation: Department of Obstetrics and Gynaecology, Semmelweis University, Budapest, Hungary.
authors.forename: Balint
authors.initials: B
authors.lastname: Nagy
authors.affiliation: Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.|Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Iben
authors.initials: I
authors.lastname: Bache
authors.affiliation: Department of Pathology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lisa Leth
authors.initials: LL
authors.lastname: Maroun
authors.affiliation: Helsinki University Hospital, Helsinki, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Avela
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Han G
authors.initials: HG
authors.lastname: Brunner
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.|School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Hubert J M
authors.initials: HJ
authors.lastname: Smeets
authors.affiliation: Cardiac Development and Genetics, Hubrecht Institute-KNAW and University Medical Centre Utrecht, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Bakkers
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Arthur
authors.initials: A
authors.lastname: van den Wijngaard
mesh_terms: D000818:Animals; D003914:Dextrocardia / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D005333:Fetus / Q000473:pathology; D017353:Gene Deletion; D040181:Genetic Diseases, X-Linked / Q000175:diagnosis / Q000235:genetics*; D006367:HeLa Cells; D059446:Heterotaxy Syndrome / Q000175:diagnosis / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D020125:Mutation, Missense; D011247:Pregnancy; D021381:Protein Transport; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; C491595:ZIC3 protein, human