Genotypes and phenotypes of hereditary eye diseases associated with early-onset high myopia

To analyze the genotype of hereditary eye diseases with early-onset high myopia (eoHM) and its relationship with phenotype.

The families with eoHM were collected in Ningxia Eye Hospital from January 2019 to June 2020.The medical records of the probands and their family members were inquired and recorded in detail, and the relevant ocular examinations were performed.Peripheral venous blood samples were collected from patients and their family members, and whole-genome DNA was extracted.Sequence capture sequencing technology was applied to screen for disease-causing gene mutations in probands.The detected suspected pathogenic variants were verified by Sanger sequencing and were analyzed by family cosegregation analysis.According to ACMG guidelines, the pathogenicity of novel variants was evaluated.The original literature about hereditary eye diseases with eoHM was searched to analyze the relationship between mutated genes and clinical phenotype.This study protocol adhered to the Declaration of Helsinki.All subjects or their guardians were informed of the purpose and procedure of the study and signed the informed consent form.The study protocol was approved by the Ethics Committee of the People’s Hospital of Ningxia Hui Autonomous Region (No.2016018).

A total of 20 eoHM families were collected, among which pathogenic variants associated with inherited eye diseases were detected in 8 families.Of the 8 probands, two were diagnosed with familial exudative vitreoretinopathy, one with X-linked retinitis pigmentosa, one with congenital stationary nightblindness, one with Stickler syndrome, one with achromatopsia, one with Leber congenital amaurosis, and one with gyrate atrophy of the choroid and retina.The first diagnosis age of the 8 probands was 4-7 years old, and they were all diagnosed as high myopia, with a refractive status ≤-6.00 DS.Genetic tests showed that the 8 probands carried a heterozygous variant c. 313A>G (p.M105Val) in FZD4 gene, a heterozygous variant c. 14_15insAAGA (p.Asp5fs^*) in TSPAN12 gene, a heterozygous frameshift variant c. 2234_2237del (p.Arg745fs) in RPGR gene, a compound heterozygous variant of c. 481C>T (p.Gln161Ter^*) and c. 355>T (p.Arg119Cys^*) in GPR179 gene, a frameshift variant c. 1659_1660insACGGTGACCCTGGCCGTCCTGG (p.Pro554fs^*) in COL2A1 gene, a compound heterozygous variant of c. 1811C>T (p.Thr604Ile^*) and c. 967G>A (p.Gly323Ser) in PDE6B gene, a compound heterozygous variant of c. 604_619delTCCACGGCACTCAGGG (p.Ser202fs^*) and c. 995G>C (p.Arg332Pro) in GUCY2D gene, a homozygous variant c. 772C>T (p.Pro241Leu) in OAT gene.Seven of them were novel variants.Compared with the previous literature, the clinical and gene phenotypes of the 8 families were analyzed in detail in this study, which provided the basis for the diagnosis of hereditary eye diseases with eoHM.

EoHM is closely related to some hereditary eye diseases, which may be the reason for the early diagnosis of children and an important clue for clinicians to detect potential hereditary eye diseases.Further clinical evaluations of ocular structure and function as well as genetic screening in children with eoHM are recommended.