Screening Laboratory Hannover, Hannover, Germany.
Institute of Clinical Chemistry, Hannover Medical School, Hannover, Germany.
Orphanet J Rare Dis. 2017 Dec 21;12(1):187. doi: 10.1186/s13023-017-0737-7.
The aim of the present study was to establish a non-invasive, fast and robust enzymatic assay to confirm fatty acid oxidation defects (FAOD) in humans following informative newborn-screening or for selective screening of patients suspected to suffer from FAOD.
MATERIAL/METHODS: The reliability of this method was tested in whole blood from FAOD patients with specific enzymatic defects. Whole blood samples were assayed in 30 medium chain- (MCADD, age 0 to 17 years), 6 very long chain- (VLCADD, age 0 to 4 years), 6 long chain hydroxy- (LCHAD, age 1 to 6 years), 3 short chain- (SCADD, age 10 to 13 years) acyl-CoA-dehydrogenase- and 2 primary carnitine transporter deficiencies (CTD, age 3 to 5 years). Additionally, 26 healthy children (age 0 to 17 years) served as controls. Whole blood samples were incubated with stable end-labeled palmitate; labeled acylcarnitines were analyzed by tandem mass spectrometry and compared with controls and between patient groups (Mann-Whitney Rank Sum Test). Concentrations of specific labeled acylcarnitine metabolites were compared between particular underlying MCADD- (ANOVA), VLCADD- and LCHADD- genetic variants (descriptive data analysis).
11 different acylcarnitines were analyzed. MCADD- (C8-, C10-carnitine, C8/C10- and C8/C4-carnitine), VLCADD- (C12-, C14:1-, C14:2-carnitine, C14:1/C12- and C14:2/C12-carnitine), LCHADD (C16-OH-carnitine) as well as CTD- deficiency (sum of all acylcarnitines) samples could be clearly identified and separated from control values as well as other FAOD, whereas the sum of all acylcarnitines was not conclusive between FAOD samples. Furthermore, C4- (SCADD), C14- (VLCADD) and C14-OH-carnitines (LCHADD) were discriminating between the FAOD groups. Metabolic parameters did not differ significantly between underlying MCADD variants; similar results could be observed for VLCADD- and LCHADD- variants.
This functional method in whole blood samples is relatively simple, non-invasive and little time consuming. It allows to identify MCADD-, VLCADD-, LCHADD- and carnitine transporter deficiencies. The genetic phenotypes of one enzyme defect did not result in differing acylcarnitine patterns in MCADD, VLCADD or LCHADD in vitro.
本研究的目的是建立一种非侵入性、快速且稳健的酶促分析方法，以在经过信息丰富的新生儿筛查后或选择性筛查疑似患有 FAOD 的患者时，确认人类的脂肪酸氧化缺陷（FAOD）。
材料/方法：在具有特定酶缺陷的 FAOD 患者的全血中测试了该方法的可靠性。在 30 例中链（MCADD，0 至 17 岁）、6 例极长链（VLCADD，0 至 4 岁）、6 例长链羟酰基辅酶 A 脱氢酶（LCHAD，1 至 6 岁）、3 例短链（SCADD，10 至 13 岁）酰基辅酶 A 脱氢酶和 2 例原发性肉碱转运体缺陷（CTD，3 至 5 岁）的全血样本中进行了测定。此外，26 名健康儿童（0 至 17 岁）作为对照。全血样本与稳定的末端标记棕榈酸孵育；通过串联质谱分析标记的酰基肉碱，并与对照和患者组进行比较（Mann-Whitney 秩和检验）。在特定的 MCADD 遗传变异（方差分析）中比较了特定标记酰基肉碱代谢物的浓度 - （ANOVA）、VLCADD 和 LCHADD- （描述性数据分析）。
分析了 11 种不同的酰基肉碱。MCADD-（C8-、C10-肉碱、C8/C10-和 C8/C4-肉碱）、VLCADD-（C12-、C14:1-、C14:2-肉碱、C14:1/C12-和 C14:2/C12-肉碱）、LCHADD（C16-OH-肉碱）以及 CTD-（所有酰基肉碱的总和）缺陷样本可以与对照值以及其他 FAOD 清楚地区分开来，而 FAOD 样本之间的所有酰基肉碱总和没有定论。此外，C4-（SCADD）、C14-（VLCADD）和 C14-OH-肉碱（LCHADD）可区分 FAOD 组。MCADD 变体之间的代谢参数无显着差异；VLCADD 和 LCHADD 变体也观察到类似的结果。
该全血样本中的功能性方法相对简单、非侵入性且耗时较少。它可以识别 MCADD、VLCADD、LCHADD 和肉碱转运体缺陷。一种酶缺陷的遗传表型在体外不会导致 MCADD、VLCADD 或 LCHADD 中酰基肉碱模式的差异。
