학술논문
Recurrent heterozygous PAX6 missense variants cause severe bilateral microphthalmia via predictable effects on DNA–protein interaction
Document Type
Original Paper
Author
Williamson, Kathleen A.; Hall, H. Nikki; Owen, Liusaidh J.; Livesey, Benjamin J.; Hanson, Isabel M.; Adams, G. G. W.; Bodek, Simon; Calvas, Patrick; Castle, Bruce; Clarke, Michael; Deng, Alexander T.; Edery, Patrick; Fisher, Richard; Gillessen-Kaesbach, Gabriele; Heon, Elise; Hurst, Jane; Josifova, Dragana; Lorenz, Birgit; McKee, Shane; Meire, Francoise; Moore, Anthony T.; Parker, Michael; Reiff, Charlotte M.; Self, Jay; Tobias, Edward S.; Verheij, Joke B. G. M.; Willems, Marjolaine; Williams, Denise; van Heyningen, Veronica; Marsh, Joseph A.; FitzPatrick, David R.
Source
Genetics in Medicine: Official journal of the American College of Medical Genetics and Genomics. 22(3):598-609
Subject
Language
English
ISSN
1098-3600
1530-0366
1530-0366
Abstract
Purpose: Most classical aniridia is caused by PAX6 haploinsufficiency. PAX6 missense variants can be hypomorphic or mimic haploinsufficiency. We hypothesized that missense variants also cause previously undescribed disease by altering the affinity and/or specificity of PAX6 genomic interactions.Methods: We screened PAX6 in 372 individuals with bilateral microphthalmia, anophthalmia, or coloboma (MAC) from the Medical Research Council Human Genetics Unit eye malformation cohort (HGUeye ) and reviewed data from the Deciphering Developmental Disorders study. We performed cluster analysis on PAX6-associated ocular phenotypes by variant type and molecular modeling of the structural impact of 86 different PAX6 causative missense variants.Results: Eight different PAX6 missense variants were identified in 17 individuals (15 families) with MAC, accounting for 4% (15/372) of our cohort. Seven altered the paired domain (p.[Arg26Gln]x1, p.[Gly36Val]x1, p.[Arg38Trp]x2, p.[Arg38Gln]x1, p.[Gly51Arg]x2, p.[Ser54Arg]x2, p.[Asn124Lys]x5) and one the homeodomain (p.[Asn260Tyr]x1). p.Ser54Arg and p.Asn124Lys were exclusively associated with severe bilateral microphthalmia. MAC-associated variants were predicted to alter but not ablate DNA interaction, consistent with the electrophoretic mobility shifts observed using mutant paired domains with well-characterized PAX6-binding sites. We found no strong evidence for novel PAX6-associated extraocular disease.Conclusion: Altering the affinity and specificity of PAX6-binding genome-wide provides a plausible mechanism for the worse-than-null effects of MAC-associated missense variants.