新疆地区6-丙酮酰四氢蝶呤合成酶缺乏致四氢生物蝶呤缺乏症的诊断和基因突变分析  

Diagnosis and mutation analysis of tetrahydrobiopterin deficiency due to 6-pyruvoyl tetrahydropterin synthase deficiency in Xinjiang

作　　者：何江[1] 杨曦[1] 史清海[1] HE Jiang;YANG Xi;SHI Qing-Hai(Department of laboratory Medicine,General Hospital of Xinjiang Military Region,Urumqi,Xinjiang 830000,China)

机构地区：[1]新疆军区总医院检验科,新疆乌鲁木齐830000

出　　处：《中国妇幼保健》2021年第19期4570-4575,共6页Maternal and Child Health Care of China

基　　金：国家自然科学基金面上项目(81871020);新疆维吾尔自治区自然科学基金面上项目(2016D01C393)。

摘　　要：目的探讨新疆地区6-丙酮酰四氢蝶呤合成酶缺乏症(PTPSD)的临床诊断和基因突变特点,为开展四氢生物蝶呤缺乏症(BH4D)患者的基因诊断和基因携带者筛查提供重要依据。方法选取2011年7月-2015年3月在新疆军区总医院确诊、治疗并随访的6例PTPSD患者为研究对象。6例高苯丙氨酸血症(HPA)患者均经血苯丙氨酸(Phe)、四氢生物蝶呤(BH4)负荷试验或Phe+BH4联合负荷试验、尿蝶呤谱分析及红细胞二氢蝶呤还原酶(DHPR)活性测定,采用基因芯片捕获、二代高通量测序等进行PTS基因突变检测,分析基因型与临床表型的关系。结果病例1、3及6均为经新生儿疾病筛查召回复查确诊HPA,初期症状为皮肤稍白、四肢肌张力正常或稍有降低,偶有惊厥,病例2、4及5未接受新生儿疾病筛查,呈现智力障碍、运动落后、肌张力异常及惊厥等症状,尿新蝶呤(N)明显增加(病例2、4及5)或者正常(病例1、3及6),生物蝶呤(B)全部明显降低,B/(B+N)%均<5%甚至<1%,DHPR酶活性测定基本正常,服用BH4或Phe+BH4 2h后,Phe浓度逐渐下降至56.89%~68.75%,4 h后下降至83.29%~90.26%,4~6 h血Phe浓度基本降至正常水平,在6例BH4D患者的12个等位基因中均发现PTS基因致病突变,最终全部诊断为PTPSD。5例患者接受BH4、左旋多巴及5-羟色氨酸等治疗后逐渐好转,1例因诊断年龄太大、未坚持药物治疗及病情严重等不良因素而最终死亡。在6例PTPSD家系中共发现6种PTS基因致病突变,包括错义突变5种:N52S、P87S、K91R、D96N及P98Q,剪切位点突变1种(IVS1-129A>G),N52S、P87S、K91R及D96N突变共占83.3%。突变形式以错义突变为主(91.7%),突变主要集中在外显子5(66.7%)、外显子2(25.0%)及内含子1(8.3%)中。IVS1-129A>G为1种国际上尚未报道的新突变。结论 PTS基因突变是导致BH4D的主要原因,N52S、P87S、K91R及D96N为新疆地区PTS基因的热点突变,联合采用基因芯片捕获和二代高通量测序技术�Objective To investigate the clinical diagnosis and distribution characterristics of 6-pyruvoyl tetrahydropterin synthase deficiency(PTPSD) in Xinjiang and to provide important evidence for gene diagnosis and sceening the carriers of tetrahydrobiopterin deficiency(BH4 D) from normal people and PTPSD family members. Methods Six PTPSD patients who were diagnosed, treated and followed up in the General Hospital of Xinjiang Military Region from July 2011 to March 2015 were selected as the research subjects.6 cases of hyperphenylalaninemia(HPA) were subjected to blood phenylalanine(Phe) detecting, tetrahydrobiopterin(BH4) loading test or combined Phe and BH4 loading test, urine poison spectrum analysis, RBC dihydropteridine reductase(DHPR) activity determination.The PTS gene mutations were analyzed by using gene chip capture and the second generation high throughput sequencing. The relationship between the genotype and clinical phenotype was analyzed. Results Three patients(case 1, 3, and 6) after recalling and screening for neonatal diseases were finally confirmed with HPA.Their initial clinical symptoms were slightly pale skin, normal or slightly reduced muscle tone in the limbs, and occasionally convulsion.The patients(case 2, 4, and 5) which were not screened for neonatal disease were presenting symptoms of mental retardation, delayed movement, abnormal muscle tone, and convulsion. The urine neopterin(N) was significantly increased(case 2, 4, and 5) or normal(case 1, 3, and 6). All bioopterin(B) were significantly decreased and B/(B+N)% were <5% or even <1%. The activity of DHPR enzyme was basically normal. After taking BH4 or Phe+BH4 for 2 h, the Phe concentrations were gradually decreased to 56.89%-68.75% and decreased to 83.29%-90.26% after 4 h. Finally, the blood Phe concentration basically returned to the normal level after 4-6 h.In all twelve alleles of 6 patients with BH4 D, all pathogenic mutations of PTS gene were found and finally all patients were diagnosed as PTPSD. Five patients were gradually improve

关 键 词：6-丙酮酰四氢蝶呤合成酶 四氢生物蝶呤缺乏症 高苯丙氨酸血症 突变分析 

分 类 号：R596[医药卫生—内科学]