目的 分析结晶样视网膜色素变性(BCD)患者的光学相干断层扫描(OCT)特点和致病基因突变情况.方法 对确诊为BCD的21例患者进行全面的眼科检查及OCT检查,观察其病变特点;并提取外周血基因组DNA,采用PCR和直接测序方法对患者进行CYP4V2基因突变筛查.结果 所有患者的典型表现为夜盲、眼底见后极部及中周部视网膜大量结晶样颗粒.此外,3例患者6眼合并角膜结晶样物质沉积.其中1例患者合并虹膜高褶型青光眼.OCT影像显示,所有患者均可见视网膜各层次内大小不一的高反射点,其中17例患者32眼有外层视网膜管腔,1眼合并网膜下纤维血管膜,3眼合并视网膜前膜.21例患者42眼中心视网膜厚度平均为(154.29±59.39)μm,中心凹下脉络膜厚度平均(151.40±51.00)μm.遗传筛查显示CYP4V2基因的c.1091-2A>G、c.992A>C、c.802-8_810del17insGC是最常见的BCD致病突变.结论 BCD患者中心视网膜及脉络膜的萎缩变薄及外层视网膜管腔等改变,可能是晚期患者中心视力下降的重要原因.外显子7、8、9是CYP4V2基因的突变热点.%Objective To investigate the optical coherence tomography (OCT) features and genetic causes of 21 patients with Bietti′s crystalline dystrophy (BCD).Methods All 21 patients diagnosed of BCD (Jan, 2013 to Sep, 2016) were included with records of complete ophthalmologic examinations, including OCT.DNA was isolated from peripheral veinous blood.PCR and direct sequencing were used to detect possible pathogenic mutations in CYP4V2 gene.Results All patients had night blindness.Plenty of glistening intraretinal crystals were found scattered in posterior pole retina.Crystalline deposits on cornea were discovered only in 6 eyes of 3 patients.One eye in 1 patient experienced co-existence of BCD and chronic angle-closure glaucoma.Retinal hyperreflective dots were present in all 42 eyes in the OCT images.Outer retinal tubulations (ORT) were detected in 32 eyes of 17 patients;subretinal fibrovascular membrane was detected in only one eye;and epiretinal membranes were revealed in 3 eyes.Central retinal thickness decreased to some extent and the average thickness was (154.29±59.39)μm.Mean subfoveal choroidal thickness was (151.40±51.00)μm.CYP4V2 mutations, c.1091-2A>G, c.992A>C and c.802-8_810del17insGC, account for the genetic causes of the 21 BCD patients.Conclusion The atrophy of central retina and choroid and formation of ORT may be responsible for low vision in late stage patients with BCD.Exon 7-9 of CYP4V2 gene are the mutational hotspots of BCD.
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