The typical course of the disease includes severe developmental delay, intractable seizures, liver failure, and death in childhood. [genecards.org]

Genetics The polymerase gamma (POLG) gene (POLG1) is located on the long arm of chromosome 15 and encodes for DNA polymerase γ, while the POLG2 gene, located on the long arm of chromosome 17, encodes for its catalytic accessory sub-unit 2,3,7. [radiopaedia.org]

Over the next five years he developed dysphagia, slurred speech and an unsteady gait. In his twenties he experienced a tingling sensation in his hands and feet, which in his thirties progressed to involve his legs, trunk and arms. [journals.plos.org]