尿GC-MS分析技术在遗传代谢缺陷病筛查诊断中的局限性  

Limitation of urease-pretreatment and organic solvent extraction pretreatment in screening and diagnosing of IEM by urine GC-MS

作　　者：江敏妍[1] 刘丽[1] 李秀珍[1] 程静[1] 蔡燕娜[1] 彭敏芝[1] 黄永兰[1] 周志红[1] 毛晓健[1] 张文[1] 李翠玲[1] 

机构地区：[1]广州医学院附属广州市妇女儿童医疗中心内分泌代谢科,510623

出　　处：《广东医学》2012年第20期3062-3066,共5页Guangdong Medical Journal

基　　金："十一五"国家科技支撑计划项目及国家科技部973项目子课题(编号:2006BAI05A07);广州市科技局科技支撑项目(编号:2010J-E231)

摘　　要：目的探讨单纯尿素酶前处理与单纯有机酸萃取前处理的尿有机酸分析在遗传代谢缺陷病筛查诊断中的应用。方法分别将58例诊断为遗传代谢缺陷病患儿急性发作期的异常尿样分别进行单纯尿素酶前处理和单纯有机酸萃取前处理,然后应用气相色谱-质谱技术对尿中代谢产物进行分析,比较经尿素酶前处理和有机酸萃取前处理后所能检测到的代谢产物谱及疾病谱特点。结果代谢产物谱结果提示,两种前处理方法均可检测各种有机酸;单纯有机酸萃取前处理法对检测酰基甘氨酸较敏感,特别是中长链酰基甘氨酸,如己酰甘氨酸和辛酰甘氨酸,敏感度达100%,特异性95%以上,但不能检测半乳糖醇、半乳糖酸及氨基酸。尿素酶前处理法对酰基甘氨酸检测不敏感。疾病谱结果提示,单纯采用有机酸萃取法对高甘氨酸血症、尿素循环障碍、苯丙酮尿症等氨基酸代谢障碍检测的灵敏度分别为0、80.0%、83.3%;对Citrin缺乏所致新生儿肝内胆汁淤积症(NICCD)的检测灵敏度为80.0%,均低于采用尿素酶前处理法,差异有统计学意义(P=0.014,P=0.027)。结论采用单纯尿素酶前处理法的尿有机酸分析有可能漏诊脂肪酸代谢障碍,应结合血酰基肉碱分析综合判断。采用单纯有机酸萃取前处理法的尿有机酸分析有可能漏诊NICCD、半乳糖血症及氨基酸代谢障碍等,应结合血浆氨基酸分析、NICCD基因分析等,以提高疾病的阳性诊断率。Objective To investigate the applicability and limitation of urease pretreatment and organic solvent extraction pretreatment in screening and diagnosing inborn errors of metabolism（IEM） by urine GC-MS analysis.Methods Fifty-eight urine samples from cases with diagnostic IEM were analyzed by GC-MS after pretreated respectively by urease pretreatment and organic solvent extraction.Results All kinds of organic acid were detected with both urease-pretreatment and organic solvent extraction method.All kinds of acylglycines,including hexanoylglycine and capryloylglycine,were detected,with sensitivity of 100% and specificity above 95% with organic solvent extraction;however,galactitol,galactonic acid or amino acid was not detected.Urease pretreatment method was less sensitive in acyglycines detection.The sensitivities of organic solvent extraction in hyperglycinemia,urea cycle disorder,phenylketonuria and NICCD were 0,80%,83.3% and 80%,respectively,which were all significantly less than urease pretreatment（P0.05）.Conclusion False negative diagnosis of fatty acid oxidative disorder can occur using urease pretreatment alone,in which combining plasma acylcarnitine analysis is helpful.Meanwhile,false negative diagnosis of NICCD,aminoaciduria or galactosaemia can occur using organic solvent extraction pretreatment alone,in which plasma amino acid analysis and NICCD gene mutation analysis are helpful.

关 键 词：气相色谱 质谱 有机酸尿症 尿素酶预处理 萃取法 

分 类 号：R725[医药卫生—儿科]