3例植物固醇血症患儿临床表型、实验室检查、基因诊断及文献复习

Clinical phenotype, laboratory examination, gene diagnosis and literature review for 3 children with phytosterolemia

目的观察3例植物固醇血症患儿的临床诊治特点。方法回顾性分析3例不同临床表型的植物固醇血症患儿(例1和例2,双胞胎姐妹,7岁2月龄,因频繁鼻衄、腹痛就诊;例3,男,5岁7月龄,因皮肤黄色瘤就诊)实验室检查特点,用气相色谱-质谱联用仪分析患儿血清植物固醇水平,二代测序分析其致病基因,Sanger测序方法对所发现的ABCG5基因变异及父母来源进行验证。结果(1)例1、2患儿中度贫血,网织红细胞升高,总胆红素和间接胆红素升高,脾脏肿大。血涂片见较多口形红细胞等异形红细胞,大/巨大血小板增多,瑞斯托霉素诱导血小板聚集试验结果降低。尿液常规检查提示有泌尿系统出血,血脂检测结果基本正常。例3患儿轻度贫血,红细胞形态大致正常,脾脏未及肿大。大/巨大血小板增多,血小板聚集试验、胆红素、尿液常规检查结果未见异常,总胆固醇和低密度脂蛋白胆固醇明显升高。(2)3例患儿血清植物固醇含量均明显升高。(3)例1、2患儿ABCG5基因检出2个杂合变异,为复合杂合变异,c.904+1G>A和c.751C>T,变异分别来自父亲和母亲;例3患儿ABCG5基因检出1个纯合变异,c.751C>T,变异来自父母。结论初诊患儿若表现为大/巨大血小板增多与溶血性贫血、口形红细胞增多或皮肤黄色瘤,血总胆固醇、低密度脂蛋白胆固醇升高,需考虑植物固醇血症的可能,需尽早行血植物固醇含量和基因检测,以便及早干预和治疗,改善预后。

Objective To study the characteristics of clinical diagnosis and treatment for 3 children with phytosterolemia. Methods The different clinical manifestations of 3 children with phytosterolemia were retrospectively reviewed. The case 1 and case 2, who were 7 years and 2 months old twin sisters, hospitalized for frequent epistaxis and abdominal pain. The case 3, who was 5 years and 7 months old male, came to the hospital for cutaneous xanthoma. The phytosterol levels in serum of the children were analyzed by gas chromatography-mass spectrometry, and the second generation sequencing method was used to analyze the disease-causing gene. Sanger sequencing method was used to verify the ABCG5 gene mutation and parental source. Results(1) The case 1 and case 2 showed moderate anemia, raised reticulocytes, total bilirubin and indirect bilirubin as well as splenomegaly. The blood smear showed that there were more irregular red blood cells, such as oral red blood cells, increased large/giant platelets, and ristomycin-induced platelet aggregation test was decreased. The urine routine examination indicated that there was bleeding in the urinary system. The results of blood lipid test were almost normal. The case 3 showed mild anemia with normal shape of erythrocyte and normal size of spleen. The large/giant platelets increased. The results of platelet aggregation test, bilirubin and urine routine examination were in normal range, but the levels of total cholesterol and low-density lipoprotein cholesterol increased significantly.(2) The levels of serum phytosterol were significantly increased in all the 3 children.(3) Two heterozygous mutations were detectable in ABCG5 gene of case 1 and 2 which were complex heterozygous mutation, i.e., c.9041 G>A and c.751 C>T. The variations were from their father and mother respectively. In case 3, only one homozygous mutation was detectable in ABCG5 gene which originated from their parents. Conclusion When the child showed increased large/giant platelets, hemolytic anemia, erythrocytosis or xanthoma of skin and rised total cholesterol and low-density lipoprotein cholesterol at first visit, the possibility of phytosterolemia should be considered. The blood phytosterol content and gene detection should be carried out as early as possible in order to treat early and improve prognosis.