title: Mutation Spectrum of the ABCA4 Gene in 335 Stargardt Disease Patients From a Multicenter German Cohort-Impact of Selected Deep Intronic Variants and Common SNPs.
abstract: Stargardt disease (STGD1) is an autosomal recessive retinopathy, caused by mutations in the retina-specific ATP-binding cassette transporter (ABCA4) gene. To establish the mutational spectrum and to assess effects of selected deep intronic and common genetic variants on disease, we performed a comprehensive sequence analysis in a large cohort of German STGD1 patients.
  
  
  
  DNA samples of 335 STGD1 patients were analyzed for ABCA4 mutations in its 50 coding exons and adjacent intronic sequences by resequencing array technology or next generation sequencing (NGS). Parts of intron 30 and 36 were screened by Sanger chain-terminating dideoxynucleotide sequencing. An in vitro splicing assay was used to test selected variants for their splicing behavior. By logistic regression analysis we assessed the association of common ABCA4 alleles while a multivariate logistic regression model calculated a genetic risk score (GRS).
  
  
  
  Our analysis identified 148 pathogenic or likely pathogenic mutations, of which 48 constitute so far unpublished ABCA4-associated disease alleles. Four rare deep intronic variants were found once in 472 alleles analyzed. In addition, we identified six risk-modulating common variants. Genetic risk score estimates suggest that defined common ABCA4 variants influence disease risk in carriers of a single pathogenic ABCA4 allele.
  
  
  
  Our study adds to the mutational spectrum of the ABCA4 gene. Moreover, in our cohort, deep intronic variants in intron 30 and 36 likely play no or only a minor role in disease pathology. Of note, our findings demonstrate a possible modifying effect of common sequence variants on ABCA4-associated disease.
authors.affiliation: Institute of Human Genetics, University of Regensburg, Regensburg, Germany.
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Schulz
authors.affiliation: Institute of Human Genetics, University of Regensburg, Regensburg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Grassmann
authors.affiliation: Rare Retinal Disease Center, AugenZentrum Siegburg, MVZ ADTC Siegburg GmbH, Siegburg, Germany 3RetinaScience, Bonn, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kellner
authors.affiliation: Department of Ophthalmology, St. Franziskus-Hospital, Münster, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Spital
authors.affiliation: Augenarztpraxis, Berlin, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Rüther
authors.affiliation: Department of Ophthalmology, University Hospital Regensburg, Regensburg, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Jägle
authors.affiliation: University Eye Hospital Hannover Medical School, Hannover, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Hufendiek
authors.affiliation: Department of Ophthalmology, University Hospital Essen, Essen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Rating
authors.affiliation: Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Cord
authors.initials: C
authors.lastname: Huchzermeyer
authors.affiliation: Institute of Human Genetics, University of Regensburg, Regensburg, Germany.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Baier
authors.affiliation: Institute of Human Genetics, University of Regensburg, Regensburg, Germany.
authors.forename: Bernhard H F
authors.initials: BH
authors.lastname: Weber
authors.affiliation: Institute of Human Genetics, University of Regensburg, Regensburg, Germany.
authors.forename: Heidi
authors.initials: H
authors.lastname: Stöhr
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000483:Alleles; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007438:Introns; D008268:Macular Degeneration / Q000151:congenital* / Q000235:genetics / Q000378:metabolism; D008297:Male; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D012189:Retrospective Studies; D000080362:Stargardt Disease
chemical_list: C056475:ABCA4 protein, human; D018528:ATP-Binding Cassette Transporters; D004247:DNA