POLG and Decreased liver function: Genetic forms of mtDNA depletion are associated with a predominant hepatopathy, however, other organs (including muscle and brain) may also be involved (Fellman and Kotarsky 2011), such as in epileptic encephalopathy, liver failure and visual impairment in Alpers-Huttenlocher syndrome due to autosomal recessive POLG mutations (Naviaux and Nguyen 2004).