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

Clinical characteristics of X-linked infantile nystagmus in a Chinese family

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。

Objective · To identify the clinical features of a Chinese Han family with X-linked infantile nystagmus. Methods · A Chinese family with X-linked infantile nystagmus was recruited from Department of Ophthalmology in Xinhua Hospital, Shanghai Jiao Tong University School of Medicine. Peripheral blood from the members of the family was collected and molecular genetic analysis was done. The 5 patients in the family received comprehensive ocular examinations including measurement of visual acuity, degree of anomalous head posture, stereoscopic vision, binocular function, electroretinogram, visual evoked potential, optical coherence tomography, eye movement recording and cycloplegic refraction. Results · A frame-shift mutation （c.823-829delACCCTAC, p.Thr275fs） in the 9th exon of FERM domain containing protein 7 （FRMD7） in the family was found. The similar clinical features of the family included moderate impairment of visual acuity, mild astigmatism, reduced stereoscopic vision, no fusion function, and bidirectional jerk wave form. Their electroretinograms were normal, but there was a peak latency and decreased amplitudes in visual evoked potential. And the structures of maculae had no obvious abnormality. The performance of the anomalous head posture was varied. Conclusion · Thr275fs in FRMD7 protein is identifed as the main factor in the Chinese family with X-linked infantile nystagmus. The clinical features of the family show a certain degree of consistency.