Common deletion of mitochondrial DNA in a 5-year-old girl with failure to thrive, ptosis, ophthalmoplegia and ragged-red fibers

A girl aged 4 years and 10 months presented with failure to thrive, ptosis, ragged-red fibers and the common 4.9 kb mitochondrial DNA deletion. She had elevated serum lactic and pyruvic acids. The onset was at around 18 months. There were no signs of retinitis, and abnormal renal, liver or pancreatic functions. She later developed mild ophthalmoplegia at 6 years of age. Additional features of chronic progressive external ophthalmoplegia (CPEO) or Kearns–Sayre syndrome (KSS) are the conditions that should be watched and investigated in the long-term follow-up of this girl.