线粒体dna聚合酶是异三聚体，由一个副亚单位的同二聚体和一个催化亚单位组成。该基因编码的蛋白质是线粒体dna聚合酶的催化亚单位。编码的蛋白质在其n-末端附近含有一个可能是多态性的聚谷氨酸束。该基因的缺陷是渐进性外眼肌麻痹的原因，线粒体DNA缺失1（PUA1），感觉性共济失调神经病变构音障碍和眼肌麻痹（SANDO），Alper-HuttutoLokes综合征（AHS），和线粒体神经胃肠性脑病综合征（MNGEE）。在这个基因中发现了两个编码相同蛋白质的转录变体。

Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. The encoded protein contains a polyglutamine tract near its N-terminus that may be polymorphic. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE). Two transcript variants encoding the same protein have been found for this gene.