Naushad Shaik Mohammad, Jain Jamal Md Nurul, Prasad Chintakindi Krishna, Naik Usha, Akella Radha Rama Devi
Indian J Biochem Biophys. 2013 Oct;50(5):474-8.
In order to ascertain whether autistic children display characteristic metabolic signatures that are of diagnostic value, plasma amino acid analyses were carried out on a cohort of 138 autistic children and 138 normal controls using reverse-phase HPLC. Pre-column derivatization of amino acids with phenyl isothiocyanate forms phenyl thio-carbamate derivates that have a lamba(max) of 254 nm, enabling their detection using photodiode array. Autistic children showed elevated levels of glutamic acid (120 +/- 89 vs. 83 +/- 35 micromol/L) and asparagine (85 +/- 37 vs. 47 +/- 19 micromol/L); lower levels of phenylalanine (45 +/- 20 vs. 59 +/- 18 micromol/L), tryptophan (24 +/- 11 vs. 41 +/- 16 micromol/L), methionine (22 +/- 9 vs. 28 +/- 9 micromol/L) and histidine (45 +/- 21 vs. 58 +/- 15 micromol/L). A low molar ratio of (tryptophan/large neutral amino acids) x 100 was observed in autism (5.4 vs 9.2), indicating lesser availability of tryptophan for neurotransmitter serotonin synthesis. To conclude, elevated levels of excitatory amino acids (glutamate and asparagine), decreased essential amino acids (phenylalanine, tryptophan and methionine) and decreased precursors of neurotransmitters (tyrosine and tryptophan) are the distinct characteristics of plasma amino acid profile of autistic children. Thus, such metabolic signatures might be useful tools for early diagnosis of autism.
为了确定自闭症儿童是否表现出具有诊断价值的特征性代谢特征，我们使用反相高效液相色谱法对138名自闭症儿童和138名正常对照儿童进行了血浆氨基酸分析。氨基酸与异硫氰酸苯酯进行柱前衍生反应，形成苯硫代氨基甲酸酯衍生物，其最大吸收波长为254nm，可使用光电二极管阵列进行检测。自闭症儿童的谷氨酸水平升高（120±89 vs. 83±35μmol/L）和天冬酰胺水平升高（85±37 vs. 47±19μmol/L）；苯丙氨酸水平降低（45±20 vs. 59±18μmol/L）、色氨酸水平降低（24±11 vs. 41±16μmol/L）、蛋氨酸水平降低（22±9 vs. 28±9μmol/L）和组氨酸水平降低（45±21 vs. 58±15μmol/L）。在自闭症患者中观察到（色氨酸/大中性氨基酸）×100的摩尔比很低（5.4 vs 9.2），这表明色氨酸用于神经递质5-羟色胺合成的可用性较低。总之，兴奋性氨基酸（谷氨酸和天冬酰胺）水平升高、必需氨基酸（苯丙氨酸、色氨酸和蛋氨酸）水平降低以及神经递质前体（酪氨酸和色氨酸）水平降低是自闭症儿童血浆氨基酸谱的明显特征。因此，这种代谢特征可能是自闭症早期诊断的有用工具。
