Abstract
Purpose:
To report the identification of a novel missense mutation in the UBIAD1 gene in an individual with a corneal phenotype consistent with Schnyder corneal dystrophy (SCD).
Methods:
A slit lamp examination was performed on a 47-year-old woman of mixed Asian and Caucasian descent without a family history of corneal disorders. After informed consent was obtained, genomic DNA was isolated from saliva. The exons and exon-intron boundaries of the UBIAD1 gene were screened using Sanger sequencing. Identified variants were screened for in 100 control individuals. Polyphen-2 and SIFT were used to predict the functional impact of the identified mutations.
Results:
Slit lamp examination revealed prominent bilateral corneal arcus, 4.0 mm central, discoid panstromal opacification and central superficial crystalline deposition. Screening of UBIAD1 identified a novel heterozygous c.308 C>T mutation, predicted to encode a missense p.(Thr103Ile) substitution. This mutation was not identified in 200 control chromosomes. Polyphen-2 and SIFT both predicted p.(Thr103Ile) to be damaging to normal protein function.
Conclusions:
We present a novel heterozygous missense mutation in UBIAD1 identified in a patient with SCD. The p.(Thr103Ile) mutation is located in exon 1, in which the majority of previously reported mutations have been identified. Given the reported negative family history, screening of the proband’s parents is expected to demonstrate whether this represents the first confirmed de novo UBIAD1 mutation associated with SCD.