title: Genetic and functional analyses of ZIC3 variants in congenital heart disease.
abstract: Mutations in zinc-finger in cerebellum 3 (ZIC3) result in heterotaxy or isolated congenital heart disease (CHD). The majority of reported mutations cluster in zinc-finger domains. We previously demonstrated that many of these lead to aberrant ZIC3 subcellular trafficking. A relative paucity of N- and C-terminal mutations has, however, prevented similar analyses in these regions. Notably, an N-terminal polyalanine expansion was recently identified in a patient with VACTERL, suggesting a potentially distinct function for this domain. Here we report ZIC3 sequencing results from 440 unrelated patients with heterotaxy and CHD, the largest cohort yet examined. Variants were identified in 5.2% of sporadic male cases. This rate exceeds previous estimates of 1% and has important clinical implications for genetic testing and risk-based counseling. Eight of 11 were novel, including 5 N-terminal variants. Subsequent functional analyses included four additional reported but untested variants. Aberrant cytoplasmic localization and decreased luciferase transactivation were observed for all zinc-finger variants, but not for downstream or in-frame upstream variants, including both analyzed polyalanine expansions. Collectively, these results expand the ZIC3 mutational spectrum, support a higher than expected prevalence in sporadic cases, and suggest alternative functions for terminal mutations, highlighting a need for further study of these domains.
authors.forename: Jason
authors.initials: J
authors.lastname: Cowan
authors.forename: Muhammad
authors.initials: M
authors.lastname: Tariq
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Ware
mesh_terms: D000818:Animals; D018389:Codon, Nonsense; D015331:Cohort Studies; D005260:Female; D016368:Frameshift Mutation; D014644:Genetic Variation; D006330:Heart Defects, Congenital / Q000235:genetics* / Q000473:pathology; D059446:Heterotaxy Syndrome / Q000235:genetics* / Q000473:pathology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D020125:Mutation, Missense; D041681:NIH 3T3 Cells; D010455:Peptides / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D021381:Protein Transport; D054829:RING Finger Domains / Q000235:genetics; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018389:Codon, Nonsense; D018398:Homeodomain Proteins; D010455:Peptides; D014157:Transcription Factors; C491595:ZIC3 protein, human; C019529:polyalanine