Novel mutation c.980_983delATTA compound with c.986C>A mutation of the FRMD7 gene in a Chinese family with X-linked idiopathic congenital nystagmus

Objective:To screen mutations in FERM domain-containing protein 7(FRMD7) gene in two Chinese families with X-linked idiopathic congenital nystagmus(XLICN).Methods:Common ophthalmic data and peripheral blood of two Chinese XLICN families(families A and B) were collected after informed consent.Genomic DNA was prepared from the peripheral blood of members of the two families and from 100 normal controls.Mutations in the FRMD7 gene were determined by directly sequencing polymerase chain reaction(PCR) products.Results:We identified a novel mutation c.980_983delATTA compound with c.986C>A mutation in the 11th exon of FRMD7 in family B,and a previously reported splicing mutation c.782G>C(p.R261G) in family A.The mutations were detected in patients and female carriers,while they were absent in other relatives or in the 100 normal controls.Conclusions:Our results expand the spectrum of FRMD7 mutations in association with XLICN,and further confirm that the mutations of FRMD7 are the underlying molecular mechanism for XLICN.

X染色体连锁显性遗传婴儿眼球震颤家系的临床特征研究

目的·研究1个中国汉族X染色体连锁显性遗传婴儿眼球震颤家系的临床特征。方法·收集上海交通大学医学院附属新华医院眼科就诊的1个X染色体连锁显性遗传婴儿眼球震颤家系,采集所有家系成员外周血进行分子遗传学分析。对家系内5位患者进行视力、代偿头位扭转角、立体视觉、双眼视功能、视觉电生理检查,及光学相干断层扫描、眼动仪检查和散瞳验光。结果·该家系突变位点为酵母功能域包含蛋白7(FERM domain containing protein 7,FRMD7)基因第9外显子上c.823-829delACCCTAC(p.Thr275fs)移码突变。该家系患者视力多为中度受损,屈光不正为轻度散光性屈光不正,立体视觉下降,双眼可同时视但无法融合,眼球震颤波形为双向冲动型波形,视网膜电图未见明显异常,视觉诱发电位表现多为峰时延迟、振幅降低,光学相干断层扫描未见视网膜黄斑部异常表现,代偿头位表现较为多样。结论·FRMD7蛋白Thr275fs是导致该家系致病的主要原因。该家系患者临床特征表现出一定程度的一致性。