Subsequently, three cases with pediatric‐onset autosomal dominant disease with varying phenotypes have been reported: a young adult with disease onset of adPEO in late teens and two unrelated infants presenting with hypotonia, seizures, and liver disease.4 With only a small number of cases reported, it is clearly evident that POLG2‐related disorders display a spectrum of clinical phenotypes with a wide range of age of onset. This evidence concerns the gene POLG2 and autosomal dominant progressive external ophthalmoplegia.