Clinical Sciences
Diagnosis of choroideremia in two Chinese families misdiagnosed as retinitis pigmentosa using next-generation sequencing
Miaomiao Wang, Zhuoshi Wang, Yan Sun, Yang Xia, Wei He
Published 2019-09-10
Cite as Chin J Exp Ophthalmol, 2019, 37(9): 719-724. DOI: 10.3760/cma.j.issn.2095-0160.2019.09.006
Abstract
ObjectiveTo identify choroideremia and retinitis pigmentosa(RP)using next-generation sequencing(NGS)technology.
MethodsA cross-sectional study was adopted.The participants were two pedigrees that was suspected of RP in previous hospital treatments in He Eye Specialist Hospital between January 2017 and December 2018.The relevant medical and family history were collected, and the family tree was plotted.The visual acuity, intraocular pressure, fundus photography, electroretinogram(ERG), B-mode ultrasond, visual field, color vision, optical coherence tomography(OCT), and slit lamp assessment were performed on all subjects.Target region sequencing and Sanger sequencing were performed, deletion insertion of large fragments was verified by real-time quantitative PCR.This study followed the Helsinki Declaration and was approved by the Ethics Committee of Shenyang He Eye Hospital(NO. IRB[2017]k002.01)
ResultsTwo known pathogenic mutations were identified in CHM gene: EX9 DEL and c. 715C>T.Furthermore, the clinical diagnosis of choroideremia was confirmed.The Family 1 proband Ⅱ1 with the EX9 DEL hemizygous mutation had a special clinical phenotype, "Star" small piece intact choroid was visible in the macular fovea of both eyes.The patients in pedigree 2 carried the pathogenic mutation c. 715C>T, the proband Ⅲ1 carried a hemizygous mutation and the reddish island area in the fovea macula was seen in both eyes.The mother Ⅱ2 and grandmother I2 of proband carried heterozygous mutations, the degree of fundus atrophy was lighter than that of the proband Ⅲ1, the fundus had a mottled appearance, the optic disc boundary was clear, the blood vessel thickness was moderate, and the exposed choroid was visible in the fundus atrophy area.
ConclusionsThis study is the first to identify two known pathogenic mutations in CHM gene, EX9 DEL and c. 715C>T in Asian Manchu and Han populations.The clinical phenotypes of female carriers with the c. 715C>t pathogenic mutation are different from those of male patients.The NGS technology may become a powerful tool to distinguish choroideremia from RP.
Key words:
Choroideremia; Mutation; Next-generation sequencing
Contributor Information
Miaomiao Wang
Liaoning He University, Shenyang 110000, China
Zhuoshi Wang
Yan Sun
Yang Xia
Wei He
