Abstract
Purpose: :
Lattice corneal dystrophy (LCD) type IV is a late-onset corneal dystrophy with amyloid deposition at a deep layer of the corneal stroma. Like other corneal dystrophies, this LCD subtype is also caused by a mutation (p.527Leu>Arg) of the TGFBI gene. Interestingly, although LCD type I has been reported world-wide, LCD type IV has been reported only in the Japanese population. In the current study, we sought to investigate whether this LCD subtype was caused by a founder mutation by performing a haplotype analysis.
Methods: :
Genomic DNAs were extracted from 8 patients with LCD type IV. As a control, genomic DNAs from 100 unrelated normal volunteers were obtained. For the haplotype analysis, the DNAs were amplified by PCR, TA-cloned, isothermally amplified, and subjected to 1-base primer extension assay against a mutation site (c.1580T>G) and 6 known single nucleotide polymorphisms (SNPs) (rs4669, rs2072239, rs7727725, rs17689879, rs6871571, and rs3792900) which are located adjacent to this mutation site.
Results: :
The haplotype analysis revealed that all of the disease-carrying alleles shared an identical haplotype while non-disease-carrying alleles had 4 different haplotypes. There is a statistical significance between the disease-carrying and the non-disease-carrying alleles (p = 0.003, Chi-square test).
Conclusions: :
LCD type IV was caused by a founder mutation of the TGFBI gene in a Japanese ancestor.
Keywords: mutations • genetics • cornea: clinical science