Corneal dystrophies are a group of predominantly rare inherited disorders. They are by definition bilateral, relatively symmetrical, and without systemic involvement, affecting corneal transparency and/or refraction. Traditional classification of corneal dystrophies is based on slit-lamp appearance, affected corneal layer and histological features. Molecular genetics has provided ultimate proof for the existence of distinct corneal dystrophies and discarded duplicates in their terminology. Currently, there are at least 16 genes with identified pathogenic variants implicated in corneal dystrophies. Herein, we summarise contemporary knowledge on genotype-phenotype correlations of corneal dystrophies, including a critical review of some reported variants, along with the understanding of the underlying pathogenic dystrophic process; essential knowledge for the development of targeted therapies.

• Klíčová slova
• corneal dystrophy, genetics, hereditary, molecular biology,
• MeSH
• dědičné dystrofie rohovky * genetika   terapie   MeSH
• fenotyp MeSH
• genetické asociační studie * MeSH
• genotyp MeSH
• lidé MeSH
• molekulární biologie MeSH
• mutace * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The genetic architecture of corneal endothelial dystrophies remains unknown in a substantial number of affected individuals. The proband investigated in the current study was diagnosed in the neonatal period with bilateral corneal opacification due to primary endothelial cell dysfunction. Neither his parents nor his sister had signs of corneal disease. Conventional karyotyping revealed a de novo translocation involving chromosomes 3 and 20, t(3;20)(q25;p11-12). Following genome and targeted Sanger sequencing analysis, the breakpoints were mapped at the nucleotide level. Notably, the breakpoint on chromosome 20 was identified to lie within the same topologically associated domain (TAD) as corneal endothelial dystrophy-associated gene OVOL2, and it is predicted to disrupt distal enhancers. The breakpoint at chromosome 3 is located within intron 2 of PFN2, which is currently not associated with any human disease. Further interrogation of the proband's genome failed to identify any additional potentially pathogenic variants in corneal endothelial dystrophy-associated genes. Disruption of a candidate cis-regulatory element and/or positional effects induced by translocation of OVOL2 to a novel genomic context may lead to an aberrant OVOL2 expression, a previously characterized disease mechanism of corneal endothelial dystrophy. Further research is necessary to explore how disruption of regulatory elements may elucidate genetically unsolved corneal endothelial dystrophies.

• MeSH
• dědičné dystrofie rohovky * genetika   diagnóza   MeSH
• genetická predispozice k nemoci MeSH
• lidé MeSH
• lidské chromozomy, pár 3 genetika   MeSH
• novorozenec MeSH
• regulační oblasti nukleových kyselin * MeSH
• rodokmen MeSH
• transkripční faktory * genetika   MeSH
• translokace genetická MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Ovol2 protein, human MeSH Prohlížeč
• transkripční faktory * MeSH

We report the phenotype of a 15-year-old female patient with anterior segment dysgenesis (ASD) caused by a novel heterozygous loss-of-function FOXC1 variant. The proband underwent an ophthalmic examination as well as a molecular genetic investigation comprising exome sequencing, a single nucleotide polymorphism array to access copy number and Sanger sequencing to exclude non-coding causal variants. There was bilateral mild iris hypoplasia with pupil deformation and iridocorneal adhesions. In addition to these features of ASD, the corneas were flat, with mean keratometry readings of 38.8 diopters in the right eye and 39.5 diopters in the left eye. There was a snail track lesion of the left cornea at the level of the Descemet membrane. The central corneal endothelial cell density was reduced bilaterally at 1964 and 1373 cells/mm2 in the right and left eyes, respectively. Molecular genetic analysis revealed that the proband was a carrier of a novel heterozygous frameshifting variant in FOXC1, c.605del p.(Pro202Argfs*113). Neither parent had this change, suggesting a de novo origin which was supported by paternity testing. We found no possibly pathogenic variants in the other genes associated with posterior corneal dystrophies or ASD. Further studies are warranted to verify whether there is a true association between snail track lesions, corneal flattening, and pathogenic variants in FOXC1.

• Klíčová slova
• FOXC1, anterior segment dysgenesis, corneal dystrophy, corneal endothelium, keratometry,
• Publikační typ
• časopisecké články MeSH