Abstract
Purpose: :
To report the phenotypic spectrum of anterior segment dysgenesis and genotyping results in monozygotic twins and their offspring.
Methods: :
We performed a thorough anterior segment slit lamp examination and external examination on the monozygotic twins and their first-degree relatives. A screen for coding sequence variants of candidate genes (FOXE3, CYP1B1, PITX2, and FOXC1) was performed. Primers were selected for all exons plus 50 bp of flanking intronic sequence to perform traditional PCR-amplification and Sanger sequencing.
Results: :
Pedigree analysis is consistent with a de-novo mutation in the monozygotic twins that is passed on to each of their offspring as an autosomal dominant trait. The phenotype in the affected individuals is variable and includes posterior embryotoxon, Axenfeld-Rieger’s anomaly, Peters’ anomaly, and secondary glaucoma. Visual acuity in the affected eyes ranged from 20/30 to No Light Perception. Both eyes from one twin and one eye of her daughter have been enucleated after multiple corneal transplant and glaucoma surgical procedures. Interestingly, affected individuals have prominent ears (bat-wing type of pinna). No pathogenic coding variants were detected in FOXE3, CYP1B1, PITX2, and FOXC1.
Conclusions: :
To our knowledge, this pedigree represents the first report of a multigenerational family with anterior segment dysgenesis that includes a pair of monozygotic twins. Genome sequencing in this unique family may yield a novel disease locus for anterior segment dysgenesis and further establish locus heterogeneity of this trait.
Keywords: genetics • anterior segment • cornea: basic science