Norman E J, Denton M D, Berry H K
Clin Chem. 1982 Jan;28(1):137-40.
Gas chromatography/mass spectrometry was used for the detection of 3-hydroxy-3-methylglutaryl-CoA lyase (EC 4.1.3.4) deficiency in double first cousins. This enzyme is in the last step of leucine catabolism and is also involved in ketogenesis. Quantitation of urinary organic acids as their cyclohexyl esters demonstrated increased concentrations of 3-hydroxy-3-methylglutaric acid, 3-methylglutaconic acid, 3-methylglutaric acid, and 3-hydroxyisovaleric acid. The procedure is more rapid, sensitive, and specific than previously reported gas-chromatographic methods for acid quantitation. The affected children initially presented with symptoms similar to Reye's syndrome; the acids were quantitated during periods of altered intake of protein and fat. Both leucine and fat intake contributed to increased acid excretion. These studies suggest that life-threatening episodes of hypoglycemia are best prevented with a low-protein, low-fat diet.
采用气相色谱/质谱法检测一对双重亲表兄妹是否缺乏3-羟基-3-甲基戊二酰辅酶A裂解酶（EC 4.1.3.4）。该酶参与亮氨酸分解代谢的最后一步，也与酮体生成有关。将尿中有机酸定量为其环己酯后发现，3-羟基-3-甲基戊二酸、3-甲基戊烯二酸、3-甲基戊二酸和3-羟基异戊酸的浓度升高。该方法比之前报道的用于酸定量的气相色谱法更快、更灵敏且更具特异性。受影响的儿童最初表现出与瑞氏综合征相似的症状；在蛋白质和脂肪摄入量改变期间对这些酸进行了定量。亮氨酸和脂肪的摄入均导致酸排泄增加。这些研究表明，采用低蛋白、低脂饮食能最好地预防危及生命的低血糖发作。
