RESUMO
Objective:To observe and determine the gene mutation site and clinical phenotype of a NDP gene mutant family, and provide a basis for the prenatal diagnosis of offspring. Methods:A pedigree investigation study. Two patients and 6 family members of a third-generation Han family with NDP gene mutation who were admitted to the Maternal and Child Health Hospital of Gansu Province from July 2019 to December 2021 were included in the study. The patients and their parents underwent the examination of pupil light reflex, strip light imaging, visual acuity evaluation, fundus color photography, and wide-field fluorescein fundus angiography (FFA). Peripheral blood of all the subjects was collected, the pathogenic genes were screened by whole exome sequencing, and NDP genes were detected by amplification of multiple ligated probes. DNA prenatal diagnosis was performed by amniocentesis at 19th weeks of the mother's third gestation. Results:Proband (Ⅲ1), male, 4 years old, full term natural delivery. At about 40 days after birth, B-mode ultrasonography indicated total retinal detachment in both eyes. Normal hearing and intelligence. Fundus examination was not performed. First sibling of proband (Ⅲ2, big younger brother), ophthalmologic examination 30 days after birth, retinal detachment in both eyes. Proband's mother (Ⅱ2) had unvascularized peripheral temporal retina in both eyes. Wide-angle FFA examination showed no vascularization of the peripheral temporal retina in both eyes, and slight leakage of peripheral vascular fluorescein. The proband's second sibling (Ⅲ3, little younger brother) was screened for neonatal eye disease 1 day after birth. No abnormalities were observed outside both eyes. Cornea and lens transparent. No abnormalities were observed in the optic disc and macula in both eyes. No vascular curvature was observed in the peripheral retina. The results of gene detection showed that there was hemizygote deletion in exon 2 of NDP gene of the proband (Ⅲ1) and its big younger brother (Ⅲ2). His mother (Ⅱ2) had heterozygosity deletion in exon 2 of NDP gene. The phenotype and genetic test results of the proband's father (Ⅱ1), uncle (Ⅱ3), maternal grandfather (Ⅰ1) and maternal grandmother (Ⅰ2) were not abnormal. Conclusions:The hemizygote deletion in exon 2 of NDP gene is a pathogenic variation in the native family. The clinical phenotypes of different genders are different. Prenatal diagnosis is an effective way to block hereditary diseases in families.