[Clinical and genetics characteristics of adult-onset cerebrotendinous xanthomatosis: analysis of a Chinese pedigree].

Objective: Clinical manifestations, imaging findings, pathologic features, and genetic mutations of Chinese adult patients with cerebrotendinous xanthomatosis (CTX) were analyzed in order to achieve a greater understanding of CTX that can improve early detection, diagnosis, and treatment. Methods: Clinical data including medical history, neurologic and auxiliary examinations, imaging findings, and genetic profile were collected for an adult patient with CTX admitted to the Sixth Medical Center of Chinese People's Liberation Army General Hospital in August 2020. Additionally, a systematic review of genetically diagnosed Chinese adult CTX cases reported in major databases in China and other countries was performed and age of onset, first symptoms, common signs and symptoms, pathologic findings, imaging changes, and gene mutations were analyzed. Results: The proband was a 39-year-old female with extensive, early-onset nervous system manifestations including cognitive dysfunction and ataxia. Systemic lesions included juvenile cataract and a tendon mass. Cranial magnetic resonance imaging revealed cerebral atrophy, symmetric white matter changes predominantly in the pyramidal tract, and lesions in the cerebellar dentate nucleus. A novel homozygous mutation in the sterol-27-hydroxylase (CYP27A1) gene (c.1477-2A>C) was identified. There were no family members with similar clinical presentation although some were carriers of the c.1477-2A>C mutation. The patient showed a good response to deoxycholic acid treatment. Totally there were 56 cases of adult CTX patients in China, mostly in East China (31/56, 55.4%), at a male-to-female ratio of 1.8 to 1. Multiple organs and tissues including nervous system, tendon, lens, lung, and skeletal muscle were affected in these cases. The most common neurologic manifestations were cognitive dysfunction (44/52, 84.6%) and ataxia (44/51, 86.3%). The cases were characterized by early onset, chronic progressive damage of multiple systems, long disease course, and delayed diagnosis, making the disease difficult to manage clinically and resulting in poor prognosis. The 2 most common genetic mutations in Chinese adult CTX patients were c.1263+1G>A and c.379C>T. Exon 2 of the CYP27A1 gene was identified as a mutation hot spot. Conclusions: Chinese adult patients with CTX have complex clinical characteristics, a long diagnostic cycle, and various CYP27A1 gene mutations. Early diagnosis and intervention can improve the prognosis of these patients.目的： 分析并总结中国成年脑腱黄瘤病（CTX）患者的临床表现、影像学改变、病理特点以及基因变异等方面特征，提高临床医生对于CTX的认识，以利于早发现、早诊断、早治疗。 方法： 收集解放军总医院第六医学中心2020年8月就诊的1例CTX患者家系病史、神经系统查体、辅助检查、影像学及基因检查结果等临床资料，系统检索国内外主要数据库报道的经基因诊断的中国成年CTX病例，回顾性分析发病年龄、首发症状、常见症状体征、病理结果、头颅磁共振成像（MRI）影像学改变及基因突变特征。 结果： 患者女性，39岁，神经系统及其他系统广泛受累且发病较早，神经系统主要表现为认知功能障碍及共济失调，其他系统受累主要表现为幼年白内障、肌腱肿物。头颅MRI以脑萎缩、对称性锥体束为主的白质病变和小脑齿状核对称性病变为特征性表现。患者固醇-27-羟化酶（CYP27A1）基因存在c.1477-2A>C纯合突变，为全球首例。鹅脱氧胆酸治疗效果较好。该家系中无类似临床表现患者，但发现了c.1477-2A>C突变基因携带者。结合文献，发现中国成年CTX患者多报道于华东地区55.4%（31/56），男女性别比为1.8∶1，发病年龄为9（6，17）岁，病程23（10，29）年，确诊年龄20~49（35±7）岁，可以累及神经系统、肌腱、晶状体、肺、骨骼肌等多个器官组织，神经系统受累最为明显，以认知功能障碍84.6%（44/52）、共济失调86.3%（44/51）为其常见表现。本病具有起病早，多系统慢性进行性损害，病程长，诊断晚，预后差等特点。经基因诊断的中国成年CTX患者最常见的两种基因突变是c.1263+1G>A和c.379C>T，CYP27A1基因2号外显子是突变的热点区域。 结论： 中国成年CTX患者临床特征复杂，诊断周期长，基因突变位点较多，早期诊治可改善预后，需引起关注。.