Genotype and clinical phenotype analysis of posterior pleomorphic corneal dystrophy associated with a new variant of ZEB1 gene

Objective  To analyze the pathogenicity and clinical phenotype associated with a newly identified heterozygous variant in the ZEB1 gene that causes posterior pleomorphic corneal dystrophy (PPCD).

Methods  A pedigree study was conducted.Clinical data of four people in 2 generations from one family with PPCD who visited Henan Eye Hospital in October 2023 were collected, including 3 patients. Relevant ophthalmic examinations were performed.Best corrected visual acuity, slit lamp microscopy, intraocular pressure, Pentacam corneal topography, Corvis ST corneal biomechanics analyzer, corneal endothelial microscopy, swept-source anterior segment coherence optical tomography (CASIA), laser scanning confocal microscopy, and ultra-wide-field fundus photography were performed to examine clinical phenotypes.Peripheral venous blood samples were collected from family members to extract genomic DNA, and whole exome sequencing was performed.Sanger sequencing and pedigree co-segregation analysis were carried out.Conservation analysis was performed using GERP+ + and Clustal Omega software, and the pathogenicity of the variant was assessed according to American College of Medical Genetics and Genomics (ACMG) guidelines.This study protocol adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[15]).All subjects or guardian signed informed consent.

Results  This family conformed to autosomal dominant inheritance.Under a slit-lamp microscope, corneal endothelial vesicular lesions in both eyes could be seen in the proband, her father and her brother.Under a laser scanning confocal microscope, endothelial cells were missing at the lesions, and some were crater-like changes, and some lesions were circular or elliptical vesicular, and no other systemic abnormalities were observed.The ocular and physical examination of the proband’s mother showed no abnormalities.Genetic testing results showed that the proband, her father and her brother all carried the ZEB1c.790G>A (p.Gly264Arg) heterozygous variant, but her mother did not carry the variantion.Sanger sequencing verified that this variantion was co-segregated within the family.The variantion is a newly discovered missense mutation that had not been reported in the Thousand Genomes Project, Genome Aggregation Database, and ExAC database.The prediction results of the variant by MutationTaster, SIFT, PROVEAN, VESST3, DANN, FATHMM-MKL, CADD, fitCons and other software were harmful, and GERP+ +, Weblogo, Clustal Omega analysis showed that the amino acids affected by the variant were highly conservative.According to the ACMG Guidelines, this variation was possible pathogenic.

Conclusions  The identification of the missense mutation c. 790G>A (p.Gly264Arg) in the ZEB1 gene within this PPCD family provides new insights into the genetic basis of PPCD and the variant may be the pathogenic variant of in this family.

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