Leukoencephalopathy with a case of heterozygous POLG mutation mimicking mitochondrial neurogastrointestinal encephalomyopathy (MNGIE).

Diseases due to mutations of polymerase γ (POLG) usually present with progressive external ophthalmoplegia. However, a few studies have been reported on POLG1 mutations with the mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)-like phenotype. All cases with POLG1 mutations mimicking MNGIE have never shown leukoencephalopathy on brain magnetic resonance imaging (MRI) or demyelinating polyneuropathy. We present a 26-year-old male with gait disturbance, recurrent bowel obstruction, peripheral neuropathy, ophthalmoplegia or ptosis, which represented MNGIE phenotype. Though he displayed demyelinating peripheral neuropathy or leukoencephalopathy on brain MRI, genetic analysis revealed heterozygous mutation in POLG1 gene. We report for the first time two newly characteristics in our patient with heterozygous POLG1 mutations with the MNGIE-like phenotype: leukoencephalopathy and demyelinating polyneuropathy.