Heterozygous deletions at the ZEB1 locus verify haploinsufficiency as the mechanism of disease for posterior polymorphous corneal dystrophy type 3.
A substantial proportion of patients with posterior polymorphous corneal dystrophy (PPCD) lack a molecular diagnosis. We evaluated 14 unrelated probands who had a clinical diagnosis of PPCD who were previously determined to be negative for mutations in ZEB1 by direct sequencing. A combination of techniques was used including whole-exome sequencing (WES), single-nucleotide polymorphism (SNP) array copy number variation (CNV) analysis, quantitative real-time PCR, and long-range PCR. Segregation of potentially pathogenic changes with disease was confirmed, where possible, in family members. A putative run of homozygosity on chromosome 10 was identified by WES in a three-generation PPCD family, suggestive of a heterozygous deletion. SNP array genotyping followed by long-range PCR and direct sequencing to define the breakpoints confirmed the presence of a large deletion that encompassed multiple genes, including ZEB1. Identification of a heterozygous deletion spanning ZEB1 prompted us to further investigate potential CNVs at this locus in the remaining probands, leading to detection of two additional heterozygous ZEB1 gene deletions. This study demonstrates that ZEB1 mutations account for a larger proportion of PPCD than previously estimated, and supports the hypothesis that haploinsufficiency of ZEB1 is the underlying molecular mechanism of disease for PPCD3.
Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic.|Department of Ophthalmology, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic.
Petra
P
Liskova
UCL Institute of Ophthalmology, London, UK.
Cerys J
CJ
Evans
UCL Institute of Ophthalmology, London, UK.
Alice E
AE
Davidson
Department of Pediatric Hematology and Oncology, Second Faculty of Medicine, University Hospital Motol, Charles University in Prague, Prague, Czech Republic.
Marketa
M
Zaliova
Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic.
Lubica
L
Dudakova
Gennet, Centre for Fetal Medicine and Reproductive Genetics, Prague, Czech Republic.
Marie
M
Trkova
Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic.
Viktor
V
Stranecky
UCL Institute of Ophthalmology, London, UK.|Moorfields Eye Hospital, London, UK.
Nicole
N
Carnt
UCL Genetics Institute, London, UK.
Vincent
V
Plagnol
Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.|Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand.
Andrea L
AL
Vincent
Moorfields Eye Hospital, London, UK.
Stephen J
SJ
Tuft
UCL Institute of Ophthalmology, London, UK.
Alison J
AJ
Hardcastle
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics* / Q000473:pathology; D056915:DNA Copy Number Variations; D005260:Female; D017353:Gene Deletion; D057895:Haploinsufficiency; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D000071799:Zinc Finger E-box-Binding Homeobox 1 / Q000235:genetics*
C486307:ZEB1 protein, human; D000071799:Zinc Finger E-box-Binding Homeobox 1