Supplementary Material for: Moderate Hyperhomocysteinemia along with Increased Levels of Vitamin B₁₂ in a 21-Year-Old Male with the Sanfilippo Syndrome: A Case Report

The Sanfilippo syndrome is an autosomal recessive mucopolysaccharidosis. Homocysteine and B₁₂ status have not been described in this syndrome. A 21-year-old bedridden male with the Sanfilippo syndrome was hospitalized. He was in poor nutritional status according to laboratory and somatometric findings, he had an enlarged liver, moderate aortic valve insufficiency and was under antiepileptic, antipsychotic and anti-cholinergic therapy. The patient had moderate hyperhomocysteinemia (16.9 μmol/L) with co-existing high levels of serum B₁₂ (1,765 pg/mL). In addition, cystathionine, methionine sulphoxide and certain amino acids were measured. It was hypothesized that a “functional” deficiency of vitamin B₁₂ may be due to problematic transcobalamin-vitamin B₁₂ complex dissociation. Moreover, the patient’s cardiovascular background and/or medical treatment may explain the observed hyperhomocysteinemia. B₁₂ and homocysteine status should be assessed in Sanfilippo patients. This report suggests that checking vitamin B₁₂ and homocysteine status may be useful in the Sanfilippo syndrome.

桑菲利波综合征（Sanfilippo syndrome）是一种常染色体隐性遗传性黏多糖贮积症。目前尚未见针对该综合征患者同型半胱氨酸（homocysteine）与维生素B₁₂（vitamin B₁₂）代谢状态的相关研究报道。本研究纳入1例21岁卧床不起的桑菲利波综合征男性患者并收治入院。实验室检测与人体测量学结果显示，该患者营养状况不佳，存在肝大、中度主动脉瓣关闭不全，且正接受抗癫痫、抗精神病及抗胆碱能药物治疗。该患者合并中度高同型半胱氨酸血症（血清同型半胱氨酸水平为16.9 μmol/L），同时血清维生素B₁₂水平升高（1765 pg/mL）。此外，研究还对患者血清中的胱硫醚（cystathionine）、甲硫氨酸亚砜（methionine sulphoxide）及部分氨基酸水平进行了检测。研究推测，维生素B₁₂的"功能性"缺乏可能与转钴胺素-维生素B₁₂复合物（transcobalamin-vitamin B₁₂ complex）解离异常有关；此外，患者的心血管基础疾病及/或临床用药也可能是导致其高同型半胱氨酸血症的诱因。建议对桑菲利波综合征患者的维生素B₁₂与同型半胱氨酸代谢状态进行评估。本病例报告提示，检测维生素B₁₂及同型半胱氨酸水平或可辅助桑菲利波综合征的临床诊疗。