Black Toenail Sign in MELAS Syndrome

Matthew T. Whitehead, Michael Wien, Bonmyong Lee, Nancy Bass, Andrea Gropman

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Background Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a mitochondrial disorder often causing progressive brain injury that is not confined to large arterial territories. Severe insults ultimately lead to gyral necrosis affecting the cortex and juxtacortical white matter; the neuroimaging correlate is partial gyral signal suppression on T2/FLAIR sequences that resemble black toenails. We aimed to characterize the imaging features and the natural history of MELAS-related gyral necrosis. Materials and Methods Databases at two children's hospitals were searched for brain magnetic resonance imaging studies of individuals with MELAS. Examinations with motion artifact and those lacking T2/FLAIR sequences were excluded. The location, the cumulative number, and the maximum transverse diameter of necrotic gyral lesions were assessed using T2-weighted images and T2/FLAIR sequences. Wilcoxon signed-rank test was employed to evaluate the relationship between disease duration and the number of necrotic lesions. Results One hundred twenty-four examinations from patients with 14 unique MELAS patients (16 ± 3 years) were evaluated. Six of the eight patients who developed brain lesions also developed gyral necroses (mean 13, range 0 to 44). Necrotic lesions varied in maximal diameter from 4 to 25 mm. Cumulative necrotic lesions correlated with disease duration (P < 0.001). Conclusions The black toenail sign signifying gyral necrosis is a common imaging feature in individuals with MELAS syndrome. The extent of gyral necrosis correlates with disease duration.

Original languageEnglish (US)
Pages (from-to)61-65
Number of pages5
JournalPediatric Neurology
StatePublished - Oct 1 2017


  • gyrus
  • mitochondria
  • necrosis

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Neurology
  • Developmental Neuroscience
  • Clinical Neurology


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