Abstract
Purpose :
To know the most frequent mutation in patients with oculopharyngeal muscular dystrophy who are treated at an ophthalmological hospital in Mexico City.
Methods :
Prospective, analytical and cross-sectional study was done in order to report the clinical and molecular characteristics in patients with a clinical diagnosis of oculopharyngeal muscular dystrophy, and to determine by nucleotide sequencing analysis mutations in the PABPN1 gene. Data concerning familial history of the disease, associated diseases, age of onset of major symptoms, presence of associated symptoms, past history of surgical eyelid procedures were collected for each subject. Genomic DNA was isolated from blood sample; PAPBPN1 gene was PCR-amplified using oligonucleotides and appropriate conditions; PCR products were analyzed by electrophoresis in agarose gel 1.5%, direct sequencing was achieved using the BigDye Terminator Cycle Sequencing kit and samples were analyzed in a 3130 Genetic Analyzer
Results :
Clinical and genetic information was obtained from 17 subjects (patients and relatives). All subjects were of Mexican origin. Thirteen of the 17 patients (76%) had affected siblings and/or parents. The earliest symptom was ptosis and in four patients dysphagia was the first symptom followed by ptosis. By the time of the study twelve patients had undergone palpebral surgery and four of them with surgical re-operation with frontal muscle suspension. Five patients showed an expanded (GCN) 15 mutation in the PABPN1 gene and the remaining 12 are being processed to confirm their diagnosis.
Conclusions :
The mutation arises from expansions of a trinucleotide (GNC) tract in the first exon of PABPN1 gene; non-OPMD patients exhibit a tract of 10 uninterrupted GCN triplets. Molecular testing offers a definitive OPMD diagnosis and should be considered in patients with late onset causes of ptosis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.