Plasma Amino Acid and Urine Organic Acid in Diagnosis of MELAS

멜라스 증후군 진단에서의 혈장 아미노산과 소변 유기산 분석

  • Ji-Hoon Na (Departments of Pediatrics, Gangnam Severence Hospital, Yonsei University College of Medicine) ;
  • Young-Mock Lee (Departments of Pediatrics, Gangnam Severence Hospital, Yonsei University College of Medicine)
  • 나지훈 (연세대학교 의과대학 소아청소년과학교실) ;
  • 이영목 (연세대학교 의과대학 소아청소년과학교실)
  • Published : 2023.06.30

Abstract

Purpose: In the past, detection of metabolic abnormalities in plasma amino acid (PAA) and urine organic acid (UOA) has been widely used to diagnose clinical mitochondrial diseases, such as mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). In this study, the diagnostic values of PAA and UOA were reviewed, and their effectiveness in the diagnosis of MELAS was examined retrospectively. Methods: Blood and urine samples at the time of diagnosis were collected from all clinically diagnosed MELAS patients (n=31), and PAA and UOA tests were performed. All samples were collected in a fasting state to minimize artifacts in the results. The difference in the ratio of abnormal metabolites of PAA and UOA at initial diagnosis was statistically compared between the MELAS with genetic confirmation (n=19, m.3243A>G mutation) and MELAS without genetic confirmation (n=12) groups. The MELAS without genetic confirmation group was used as control. Results: Comparison of PAA and UOA between the two groups revealed that no abnormal metabolites showed characteristic differences between gene-confirmed MELAS patients with and those without genetic confirmation. Conclusions: Abnormal values of metabolites in PAA or UOA might be useful as a screening test but are not sufficient to diagnose MELAS patients.

목적: 과거에는 혈장 아미노산 및 소변 유기산의 대사 이상 검출이 멜라스 증후군과 같은 임상적인 미토콘드리아 질환을 진단하는 데 널리 사용되었다. 본 연구에서는 혈장 아미노산 및 소변 유기산의 진단적 가치를 고찰하고, 멜라스 증후군 진단에 있어 이들의 유효성을 후향적으로 살펴보았다. 방법: 임상적으로 진단된 모든 멜라스 증후군 환자(n=31)로부터, 진단 당시의 혈액 및 소변 검체를 채취하여 혈장 아미노산 및 소변 유기산 검사를 시행하였다. 모든 샘플은 결과의 인위적 오류를 최소화하기 위해 금식 상태에서 수집되었습니다. 유전자로 진단된 멜라스 증후군 환자(n=19, m.3243A>G 돌연변이)와 유전자로 진단되지 않은 멜라스 증후군 환자(n=12) 그룹 간에 초기 진단 시 혈장 아미노산 및 소변 유기산의 비정상 대사물질 비율의 차이를 통계적으로 비교하였다. 유전자로 진단되지 않은 멜라스 증후군 환자군을 대조군으로 사용하였다. 결과: 두 그룹 간의 혈장 아미노산과 소변 유기산을 비교한 결과, 유전자로 진단된 멜라스 증후군 환자와 유전자로 진단되지 않은 멜라스 증후군 환자 간에 특징적인 차이를 보이는 비정상적인 대사 산물이 없는 것으로 나타났다. 결론: 혈장 아미노산 또는 소변 유기산의 비정상적인 대사물질 값은 멜라스 증후군의 진단에 있어서 선별 검사로 유용할 수 있지만 진단하기에는 충분하지 않다.

Keywords

Acknowledgement

The authors are grateful to all staff members, doctors, and statistical consultants who were involved in this study.

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