USH2A基因突变致非综合征性视网膜色素变性的临床表型分析

Clinical phenotype of nonsyndromic retinitis pigmentosa with compound heterozygous mutations of USH2A

  • 摘要: 目的 分析一视网膜色素变性(retinitis pigmentosa,PR)家系成员的临床表型特征,确定其遗传类型,并筛选可疑致病基因。 方法 选取2016年3月就诊于解放军总医院眼科门诊的一山东视网膜色素变性家系,该家系3代共21名成员,其中4名患者(3女1男),17名非患者,详细询问病史、家族史,采集其中8名成员的外周血(包括4名患者,4名非患者),并对这8名成员进行眼科检查,包括裸眼视力、最佳矫正视力、眼压、裂隙灯检查、色觉、眼底检查、光学相干断层成像术、视网膜电图、视野,绘制家系图谱,对收集的临床资料进行分析,确定该家系的临床分型,并筛选可疑致病基因的突变位点。 结果 该家系中4名患者均有视野缺损,出现色盲,视力不同程度下降,彩色眼底像可见视盘色蜡黄,血管变细,视网膜有骨细胞样色素沉着。4名患者明确诊断为非综合征性视网膜色素变性,其中2代2名患者较3代2名患者症状出现时间更早,症状更重。 结论 该家系为常染色体隐性遗传的非综合征性视网膜色素变性家系,可能为USH2A基因上两个位点复合杂合突变所致。

     

    Abstract: Objective To study the phenotypic characteristics and genetic classification of nonsyndromic retinitis pigmentosa in a Chinese family, and screen the disease-causing gene mutations. Methods The family in the study came from Shandong Province, which included 3 generations with 21 members (4 patients, 17 healthy individuals). The peripheral venous blood of 8 individuals(4 patients, 4 healthy individuals) in the family were collected. Ophthalmological examinations including uncorrected visual acuity, best corrected visual acuity, biomicroscopy of the anterior eye segment, applanation tonometry, fundus examination, spectral-domain optical coherence tomography (SD-OCT), and electroretinogram (ERG) were performed to the eight members. A pedigree figure was drawn after the history taking. Then, DNA isolation and sequencing were performed to determine the inheritance pattern and screen the suspected mutations. Results Night blindness, decreased visual acuity and visual field constriction were observed in four patients, and fundus photography showed a waxy yellow optic nerve head,attenuation of vessels, bone spicule deposits in the retina. The four patients in the family were all diagnosed as nonsyndromic retinitis pigmentosa, and symptom emerged earlier in Ⅲ 2 and Ⅲ 5 of the third generation thanⅡ 7 andⅡ9 of the second generation. Conclusion The USH2A gene is the disease-causing gene of the family, and its inheritance pattern is autosomal recessive. Compound heterozygous mutations in USH2A (c.4649C> A and c.970G> A) may cause the pathological changes.

     

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