Classical homocystinuria (HCU) is characterized by increased plasma levels of total homocysteine (tHcy) and methionine (Met). Treatment may involve supplementation of B vitamins and essential amino acids, as well as restricted Met intake. Dysbiosis has been described in some inborn errors of metabolism, but has not been investigated in HCU. The aim of this study was to investigate the gut microbiota of HCU patients on treatment. Six unrelated HCU patients (males = 5, median age = 25.5 years) and six age-and-sex-matched healthy controls (males = 5, median age = 24.5 years) had their fecal microbiota characterized through partial 16S rRNA gene sequencing. Fecal pH, a 3-day dietary record, medical history, and current medications were recorded for both groups. All patients were nonresponsive to pyridoxine and were on a Met-restricted diet and presented with high tHcy. Oral supplementation of folate (n = 6) and pyridoxine (n = 5), oral intake of betaine (n = 4), and IM vitamin B12 supplementation (n = 4), were reported only in the HCU group. Patients had decreased daily intake of fat, cholesterol, vitamin D, and selenium compared to controls (p < 0.05). There was no difference in alpha and beta diversity between the groups. HCU patients had overrepresentation of the Eubacterium coprostanoligenes group and underrepresentation of the Alistipes, Family XIII UCG-001, and Parabacteroidetes genera. HCU patients and controls had similar gut microbiota diversity, despite differential abundance of some bacterial genera. Diet, betaine, vitamin B supplementation, and host genetics may contribute to these differences in microbial ecology.

中文翻译：

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患有经典高半胱氨酸尿症的患者肠道菌群是否有不良作用？

经典高半胱氨酸尿症（HCU）的特征在于血浆总高半胱氨酸（tHcy）和蛋氨酸（Met）的水平升高。治疗可能涉及补充B族维生素和必需氨基酸，以及限制Met摄入。已在某些先天性代谢错误中描述了营养不良，但尚未在HCU中进行研究。这项研究的目的是调查接受治疗的HCU患者的肠道菌群。六个无关的HCU患者（男性= 5，中位年龄= 25.5岁）和六个年龄和性别匹配的健康对照组（男性= 5，中位年龄= 24.5岁）通过部分16S rRNA基因测序对粪便微生物群进行了表征。两组均记录粪便pH值，3天饮食记录，病史和当前用药情况。所有患者均对吡ido醇无反应，且饮食均受Met限制，且tHcy较高。仅在HCU组中报告了口服叶酸（n = 6）和吡ido醇（n = 5），口服甜菜碱（n = 4）和IM维生素B12补充（n = 4）。与对照组相比，患者的脂肪，胆固醇，维生素D和硒的每日摄入量减少（p <0.05）。两组之间的alpha和beta多样性没有差异。HCU患者的古细菌为真杆菌，而Alistipes，XIII家族UCG-001和Parabacteroidetes属的代表性不足。尽管某些细菌属的丰度不同，HCU患者和对照组的肠道菌群多样性相似。饮食，甜菜碱，维生素B补充剂，