尿素酶预处理-气相色谱-质谱法诊断琥珀酸半醛脱氢酶缺陷病

本文探讨琥珀酸半醛脱氢酶(succinic semialdehyde dehydrogenase，SSADH)缺陷病各尿液标志物的气相色谱-质谱法(Gas Chromatography-Mass Spectrometry，GC-MS)分析特征。收集SSADH患儿的尿液标本，经去尿素、加内标(正十七酸)、除蛋白、真空干燥处理，残余物进行三甲基硅烷化衍生后进样行GC-MS法分析。尿液中可检测到明显的4-羟基丁酸、2，4-二羟基丁酸、3，4-二羟基丁酸和4，5-二羟基己酸信号。在TIC图上，其绝对保留时间(相对保留时间)分别是6．32min(0．434)，7．80min(0．536)，7．94min(0．546)，8．80min，8．90min(0．605，0．612)。在质谱图上，其特征离子(m／z，TMS)分别是M-15(233，2)，M-15(321，3)，M-15(321，3)，M-15(349，3)。GC-MS法分离鉴定尿液代谢成分，可作为诊断该病的一种可靠手段。

Urease Pretreatment-Gas Chromatography-Mass Spectrometry in the diagnosis of succinic semialdehyde dehydrogenase deficiency

To explore the analytic characteristics of the urinary markers of succinic semialdehyde dehydrogenase (SSADH) deficiency, by gas chromatography-mass spectrometry(GC-MS),urine sample of a child with SSADH deficiency was collected, urea was decomposed with urease, n-heptadecanoic acid was added as an internal standard,protein was denaturated with ethanol and precipitate was removed by centrifugation, evaporation was performed to dryness, the residue was trimethylsilylly derivatized with BSTFA/TMCS, and then analyzed with GC-MS.Large quantity of 4-hydroxybutyric acid, 2,4-dihydroxybutyric, 3,4-dihydroxybutyric acid and 4,5-dihydroxyhexanoic acid, were detected in the urine sample. In TIC profile, their retention time(relative retention time) were 6.32min(0.434), 7.80min(0.536), 7.94min (0.546), and 8.80min,8.90min(0.605,0.612), respectively, with charateristic ions, in mass spectrums, M-15(233,2), M-15(321,3), M-15(321,3),and M-15(349,3), respectively. Analysis of urinary metabolites by GC-MS is a reliable tool for the diagnosis of SSADH deficiency.