Abstract
Purpose :
The purpose of this work is to report a novel gelsolin amiyoidosis mutation causing lattice corneal dystrophy type II in a Mexican family
Methods :
Genomic DNA was extracted from blood leukocytes of a 61 age female patient and available first degree relatives. PCR amplification of GSN exon 4 and direct sanger sequencing were performed. For next generation sequencing NGS library preparation and enrichment were performed using the Illumina TruSight One inherited disease panel. Sequence reads were mapped to the reference human genome using BWA and variant calling was performed using the GATK Unified Genotyper. Also, an eyelids biopsy was performed
Results :
Congo red stain reveals strands of amyloid perivascular and beneath Bowman layer, anterior and middle stroma, and around pilar units. Next generation sequencing of index case provided adequate coverage of the clinical exome (>91.0% and 90.8% of the exome showed >10X depth of coverage). After filtering, a missense variant was identified at exon 12 of the GSN gene (NM_000177.4: c.1631T>G; NP_000168.1: p.Met544Arg; chr9:121326573T>G). This variant was confirmed by sanger sequencing in DNA from all available affected relatives, including a young individual with mild Lattice corneal dystrophy. no evidence of systemic disease
Conclusions :
GSN amyloid accumulates in the dermis, resulting in dermatologic abnormalities, cutis laxa, or thickened and loosened skin. These symptoms, and the facial paresis, are responsible for the drooping, mask-like appearance.
This entity arises from mutations in GSN, a 70-kb gene located on chromosome 9 in the q32-34 region, which consists of 17 exons. This gene codifies for an actin-binding protein, involved in actin regulation and organization. There are two known forms of GSN as a result of alternative splicing and include a plasma GSN protein and a cytosolic GSN protein.
Early symptoms are ocular, the ophthalmologist intervention is crucial in detecting and managing the disease. Advanced corneal opacifications can be treated only by penetrating keratoplasty, with long-term fair results
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.