RESUMEN
Objective:To analyze the genotype of hereditary eye diseases with early-onset high myopia (eoHM) and its relationship with phenotype.Methods: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).Results: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. Conclusions: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.
RESUMEN
According to the onset age, high myopia can be divided into late-onset high myopia (loHM) and early-onset high myopia (eoHM). Numerous genetic studies have shown that eoHM is different from loHM.EoHM, a special type of high myopia before school age (<7 years old), is more likely influenced by genetic factors with less contribution from environment.Therefore, individuals with eoHM are an available group for the research of pathogenesis of high myopia as a monogenic disease, and eoHM should be a unique resource in searching for genes responsible for high myopia.EoHM can be divided into nonsyndromic type which only presents with simple high myopia without any ocular or systemic abnormalities, and syndromic type that has other ocular or systemic disorders.More often, eoHM is the earliest sign of some inherited ocular diseases and the first reason for children seeking medical attention, which is an important clue for clinicians to detect underlying eye diseases.Therefore, in addition to further specific clinical examination of ocular structure and function, high attention should be paid to genetic screening of eoHM in order to promote early diagnosis and effective intervention, and long-term follow-up assessment.