Abstract
Purpose: :
To report Corneal Dystrophy Molecular Analysis performed at the University of Texas Health Corneal Dystrophy Laboratory from 1996 to 2007.
Methods: :
Patients with a clinical diagnosis of a corneal dystrophy was seen by a referring eye doctor and request molecular analysis of the proband’s DNA to confirm the clinical impression. A complete package for blood collection is sent to the requesting ophthalmologists with the appropriate IRB approved forms for consent. After receiving blood sample, DNA is extracted, PCR amplified and sequenced for the exons of TGFBI/BIGH3, KRT3, KRT12 and CHST6. Once the mutation is confirmed, a report is sent to the requesting physician at no cost to the patient or referring doctor.
Results: :
Corneal dystrophy screening during this period totaled 193 with 93 affected patients. 88 mutations were found, 6 not identified and 5 still under investigation. The success rate for mutation screening was 89 %. The most common cases were TGFBI/BIGH3 mutations. R555Q mutations 11 cases, R124L 3 cases with 2 spontaneous mutations, V624M 2 cases, H626R 1 case. Keratin 12 mutations were the next most common, R630P 1 case, and M129T 3 cases. No Keratin 3 mutations were found to date. Phenotype and genotype correlations demonstrate significant phenotypic heterogeneity and clinical misdiagnosis in over 6% of our screenings especially in the dystrophies with deposits in the anterior most layers of the cornea such as Reis Buckler’s, Lattice, and Meesman’s corneal dystrophies.
Conclusions: :
The NEI sponsored eyeGene program provides clinicians the opportunity for molecular screening of corneal dystrophies at no cost to the patient. Additionally, the eyeGene program is a promising resource for offering CLIA approved genotyping allowing more accurate molecular diagnosis and more discerning phenotype and genotype correlation when studying corneal dystrophies.
Keywords: cornea: epithelium • gene screening • cornea: stroma and keratocytes