Leigh syndrome caused by the mitochondrial m.8993T>G mutation with hypocitrullinemia: a report of four cases and literature review

Abstract:

Objective To explore early diagnostic biological markers for Leigh syndrome caused by the m.8993T>G mutation.Methods A retrospective analysis was performed on the clinical data of four children diagnosed with m.8993T>G mutation-related mitochondrial disease at the Children's Hospital of Chongqing Medical University from January 2014 to January 2024. Additionally, a literature review was conducted.Results All four children had plasma amino acid and acylcarnitine analyses that revealed decreased citrulline levels, and one child was initially identified through neonatal genetic metabolic disease screening. According to the literature review, there were 26 children with mitochondrial disease and hypocitrullinemia caused by the m.8993T>G mutation (including the four children in this study). Among these, 12 children exhibited clinical phenotypes of Leigh syndrome or Leigh-like syndrome, while 18 children were identified with hypocitrullinemia and/or elevated levels of 3-hydroxyisovalerylcarnitine (C5-OH) during neonatal genetic metabolic disease screening.Conclusions Hypocitrullinemia may serve as a potential biomarker for the early diagnosis of m.8993T>G mutation-associated Leigh syndrome, detectable as early as during neonatal genetic metabolic disease screening.