Methionine adenosyltransferase I/III deficiency, also known as Mudd's disease, is a rare inborn error of methionine metabolism. Because pathophysiological mechanisms of the disease remain poorly understood, the consequences of this disorder and the need for medical management remain uncertain; likewise, the effect of medical interventions on clinical outcomes in Mudd's disease is largely unknown due to a relative lack of published longitudinal clinical data. There are few reports of adults in the medical literature affected with this disease. Clinical symptoms of reported adults range from asymptomatic to individuals with neurological, developmental, or behavioral symptoms. Here we report three siblings affected with Mudd's disease that were ascertained following an abnormal newborn screen for hypermethioninemia in the case of our index patient. All three had a variable degree of longstanding neurologic or psychiatric symptoms which had not prompted a clinical investigation for a genetic or metabolic disorder prior to identification through our clinic. While the causal association of these symptoms to the metabolic disorder remains unclear in these cases, all three patients demonstrated a degree of amelioration of symptoms and/or improvement in measurements on standardized psychiatric ratings scales when specific therapy for the metabolic disorder was instituted. The symptoms, treatment, and outcomes over the course of six years of follow-up are presented here, expanding the possible natural history of Mudd's disease.

蛋氨酸腺苷转移酶I / III缺乏症（也称为Mudd病）是蛋氨酸代谢的罕见先天性错误。由于对该疾病的病理生理机制仍知之甚少，因此该疾病的后果和医疗管理的需求仍不确定；同样，由于相对缺乏公开的纵向临床数据，医学干预对Mudd's病临床预后的影响很大程度上未知。医学文献中很少有成年人感染这种疾病的报道。报道的成年人的临床症状从无症状到具有神经，发育或行为症状的个体。在这里，我们报告三个受Mudd'影响的兄弟姐妹 在我们的索引患者的情况下，新生儿筛查异常高甲硫氨酸血症后确诊了该病。这三个人都有不同程度的长期神经或精神症状，在通过我们的诊所鉴定之前没有提示对遗传性或代谢性疾病进行临床研究。尽管在这些情况下这些症状与代谢紊乱的因果关系仍不清楚，但是当针对代谢紊乱的特定疗法被采用时，所有三名患者均表现出一定程度的症状减轻和/或标准精神病学评定量表的测量得到改善。在此介绍了六年的随访过程中的症状，治疗和预后，从而扩大了Mudd病的自然病史。这三个人都有不同程度的长期神经或精神症状，在通过我们的诊所鉴定之前没有提示对遗传性或代谢性疾病进行临床研究。尽管在这些情况下这些症状与代谢紊乱的因果关系仍不清楚，但是当针对代谢紊乱的特定疗法被采用时，所有三名患者均表现出一定程度的症状减轻和/或标准精神病学评定量表的测量得到改善。在此介绍了六年的随访过程中的症状，治疗和预后，从而扩大了Mudd病的自然病史。这三个人都有不同程度的长期神经或精神症状，在通过我们的诊所鉴定之前没有提示对遗传性或代谢性疾病进行临床研究。尽管在这些情况下这些症状与代谢紊乱的因果关系仍不清楚，但是当针对代谢紊乱的特定疗法被采用时，所有三名患者均表现出一定程度的症状减轻和/或标准精神病学评定量表的测量得到改善。在此介绍了六年的随访过程中的症状，治疗和预后，从而扩大了Mudd病的自然病史。