De Toni-Debré-Fanconi syndrome due to a palindrome-flanked deletion in mitochondrial DNA.

We report the molecular findings in a child presenting with sideroblastic anemia and proximal tubulopathy. Analysis of mitochondrial DNA (mtDNA) from fibroblasts showed the presence of a 3.3-kb single deletion in 50% of the genomes. This mutation is, unlike other previously reported deletions in tubulopathy patients, not flanked by direct repeat sequences but by palindrome sequences at the deletion breakpoints, suggesting an unusual mechanism for production of deletion. These findings further expand our knowledge of the syndrome of anemia and tubulopathy due to single deletions of mtDNA.