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Published on: May 5, 2022
Elliptical anterior iris stromal defects associated with PAX6 gene sequence changes
Sapna Sharan1, Farideh Mirzayans, Tim Footz
1Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
Summary
Novel mutations in the PAX6 gene were identified in two families with anterior segment abnormalities, including a new missense mutation. These PAX6 gene variations are linked to a range of ocular phenotypes, emphasizing the need for genetic testing.
Area of Science:
- Genetics
- Ophthalmology
- Molecular Biology
Background:
- Mutations in the PAX6 gene are associated with aniridia and other anterior segment abnormalities.
- This study investigates a novel PAX6 genotype and phenotype in two unrelated families.
Purpose of the Study:
- To report a novel PAX6 genotype and phenotype with an autosomal-dominant inheritance pattern.
- To characterize the genetic variations and associated ocular manifestations in affected individuals.
Main Methods:
- Identified two unrelated pedigrees with multi-generational affected members.
- Conducted comprehensive ocular examinations on all available family members.
- Performed molecular genetic analysis, including DNA sequencing, on affected individuals.
Main Results:
- Identified a novel phenotype with variable expression of elliptical anterior stromal iris defects, presenile nuclear sclerosis, corectopia, corneal pannus, optic nerve hypoplasia, nystagmus, and macular hypoplasia.
- One family (Family 1) had a previously reported guanine deletion in PAX6 exon 5 (position 468).
- The other family (Family 2) exhibited a novel missense mutation in PAX6 exon 5 (G469A).
Conclusions:
- PAX6 sequence changes segregated with the anterior segment phenotype in both families and were absent in controls.
- The identified mutations are located in the paired domain of the PAX6 gene.
- Recognition of these phenotypes is crucial for appropriate genetic testing and counseling for PAX6-related disorders.
