PDF(Pubmed)
Abstract：
BACKGROUND: The etiology of nephrotic syndrome can vary, with underlying metabolic diseases being a potential factor. Cobalamin C (cblC) defect is an autosomal recessive inborn error of metabolism caused by mutations in the MMACHC gene, resulting in impaired vitamin B12 processing. While cblC defect typically manifests with hematological and neurological symptoms, renal involvement is increasingly recognized but remains rare.
METHODS: We describe a 7-month-old male patient presenting with fatigue and edema. His first laboratory findings showed anemia, thrombocytopenia, hypoalbuminemia and proteinuria and further examinations reveals hemolysis in peripheric blood smear. During his follow up respiratory distress due to pleural effusion in the right hemithorax was noticed. And fluid leakage to the third spaces supported nephrotic syndrome diagnosis. The patient\'s condition deteriorated, leading to intensive care admission due to, hypertensive crisis, and respiratory distress. High total plasma homocysteine and low methionine levels raised suspicion of cobalamin metabolism disorders. Genetic testing confirmed biallelic MMACHC gene mutations, establishing the diagnosis of cblC defect. Treatment with hydroxycobalamin, folic acid, and betaine led to remarkable clinical improvement.
CONCLUSIONS: This case underscores the significance of recognizing metabolic disorders like cblC defect in atypical presentations of nephrotic syndrome. Early diagnosis and comprehensive management are vital to prevent irreversible renal damage. While cblC defects are more commonly associated with atypical hemolytic uremic syndrome, this case highlights the importance of considering cobalamin defects in the differential diagnosis of nephrotic syndrome, especially when associated with accompanying findings such as hemolysis. Our case, which has one of the highest homocysteine levels reported in the literature, emphasizes this situation again.
METHODS: We describe a 7-month-old male patient presenting with fatigue and edema. His first laboratory findings showed anemia, thrombocytopenia, hypoalbuminemia and proteinuria and further examinations reveals hemolysis in peripheric blood smear. During his follow up respiratory distress due to pleural effusion in the right hemithorax was noticed. And fluid leakage to the third spaces supported nephrotic syndrome diagnosis. The patient\'s condition deteriorated, leading to intensive care admission due to, hypertensive crisis, and respiratory distress. High total plasma homocysteine and low methionine levels raised suspicion of cobalamin metabolism disorders. Genetic testing confirmed biallelic MMACHC gene mutations, establishing the diagnosis of cblC defect. Treatment with hydroxycobalamin, folic acid, and betaine led to remarkable clinical improvement.
CONCLUSIONS: This case underscores the significance of recognizing metabolic disorders like cblC defect in atypical presentations of nephrotic syndrome. Early diagnosis and comprehensive management are vital to prevent irreversible renal damage. While cblC defects are more commonly associated with atypical hemolytic uremic syndrome, this case highlights the importance of considering cobalamin defects in the differential diagnosis of nephrotic syndrome, especially when associated with accompanying findings such as hemolysis. Our case, which has one of the highest homocysteine levels reported in the literature, emphasizes this situation again.
摘要：
背景：肾病综合征的病因各不相同，潜在的代谢性疾病是一个潜在的因素。钴胺C（cblC）缺陷是由MMACHC基因突变引起的常染色体隐性遗传先天性代谢错误，导致维生素B12加工受损。虽然cblC缺陷通常表现为血液和神经症状，肾脏受累越来越多，但仍然很少见。
方法：我们描述了一名7个月大的男性患者，表现为疲劳和水肿。他的第一个实验室发现显示贫血，血小板减少症,低蛋白血症和蛋白尿，进一步检查显示外周血涂片溶血。在他的随访过程中，发现右半胸腔胸腔积液引起的呼吸窘迫。液体泄漏到第三空间支持肾病综合征的诊断。病人的病情恶化,导致重症监护入院，高血压危象,和呼吸窘迫。高血浆总同型半胱氨酸和低蛋氨酸水平增加了对钴胺素代谢紊乱的怀疑。基因检测证实了双等位基因MMACHC基因突变，建立cblC缺陷的诊断。用羟基钴胺治疗，叶酸,和甜菜碱导致显著的临床改善。
结论：该病例强调了在肾病综合征的非典型表现中认识到代谢紊乱如cblC缺陷的重要性。早期诊断和综合治疗对于预防不可逆性肾损害至关重要。虽然cblC缺陷更常见于非典型溶血性尿毒综合征，该病例强调了在肾病综合征的鉴别诊断中考虑钴胺缺陷的重要性，特别是当与伴随的结果，如溶血。我们的案子,这是文献中报道的最高同型半胱氨酸水平之一，再次强调这种情况。
方法：我们描述了一名7个月大的男性患者，表现为疲劳和水肿。他的第一个实验室发现显示贫血，血小板减少症,低蛋白血症和蛋白尿，进一步检查显示外周血涂片溶血。在他的随访过程中，发现右半胸腔胸腔积液引起的呼吸窘迫。液体泄漏到第三空间支持肾病综合征的诊断。病人的病情恶化,导致重症监护入院，高血压危象,和呼吸窘迫。高血浆总同型半胱氨酸和低蛋氨酸水平增加了对钴胺素代谢紊乱的怀疑。基因检测证实了双等位基因MMACHC基因突变，建立cblC缺陷的诊断。用羟基钴胺治疗，叶酸,和甜菜碱导致显著的临床改善。
结论：该病例强调了在肾病综合征的非典型表现中认识到代谢紊乱如cblC缺陷的重要性。早期诊断和综合治疗对于预防不可逆性肾损害至关重要。虽然cblC缺陷更常见于非典型溶血性尿毒综合征，该病例强调了在肾病综合征的鉴别诊断中考虑钴胺缺陷的重要性，特别是当与伴随的结果，如溶血。我们的案子,这是文献中报道的最高同型半胱氨酸水平之一，再次强调这种情况。
