Late-Onset Autosomal Dominant Macular Degeneration Caused by Deletion of the CRX Gene
Yahya S., Smith CEL., Poulter JA., McKibbin M., Arno G., Ellingford J., Kämpjärvi K., Khan MI., Cremers FPM., Hardcastle AJ., Castle B., Steel DHW., Webster AR., Black GC., El-Asrag ME., Ali M., Toomes C., Inglehearn CF., Ingram S., Taylor R., Manson F., Sergouniotis P., Pontikos N., Cheetham M., Fiorentino A., Downes S., Yu J., Halford S., Broadgate S., van Heyningen V., Ambrose JC., Arumugam P., Bevers R., Bleda M., Boardman-Pretty F., Boustred CR., Brittain H., Caulfield MJ., Chan GC., Elgar G., Fowler T., Giess A., Hamblin A., Henderson S., Hubbard TJP., Jackson R., Jones LJ., Kasperaviciute D., Kayikci M., Kousathanas A., Lahnstein L., Leigh SEA., Leong IUS., Lopez JF., Maleady-Crowe F., McEntagart M., Minneci F., Moutsianas L., Mueller M., Murugaesu N., Need AC., O'Donovan P., Odhams CA., Patch C., Pereira MB., Perez-Gil D., Pullinger J., Rahim T., Rendon A., Rogers T., Savage K., Sawant K., Scott RH., Siddiq A., Sieghart A., Smith SC., Sosinsky A., Stuckey A., Tanguy M., Taylor Tavares AL., Thomas ERA., Thompson SR., Tucci A., Welland MJ., Williams E., Witkowska K., Wood SM.
Purpose: To characterize the phenotype observed in a case series with macular disease and determine the cause. Design: Multicenter case series. Participants: Six families (7 patients) with sporadic or multiplex macular disease with onset at 20 to 78 years, and 1 patient with age-related macular degeneration. Methods: Patients underwent ophthalmic examination; exome, genome, or targeted sequencing; and/or polymerase chain reaction (PCR) amplification of the breakpoint, followed by cloning and Sanger sequencing or direct Sanger sequencing. Main Outcome Measures: Clinical phenotypes, genomic findings, and a hypothesis explaining the mechanism underlying disease in these patients. Results: All 8 cases carried the same deletion encompassing the genes TPRX1, CRX, and SULT2A1, which was absent from 382 control individuals screened by breakpoint PCR and 13 096 Clinical Genetics patients with a range of other inherited conditions screened by array comparative genomic hybridization. Microsatellite genotypes showed that these 7 families are not closely related, but genotypes immediately adjacent to the deletion breakpoints suggest they may share a distant common ancestor. Conclusions: Previous studies had found that carriers for a single defective CRX allele that was predicted to produce no functional CRX protein had a normal ocular phenotype. Here, we show that CRX whole-gene deletion in fact does cause a dominant late-onset macular disease.