Mitochondrial chromosomal abnormaity leads to

Diseases caused by mutations in mitochondrial genes are rare. Because mitochondrial DNA encodes enzymes involved in oxidative phosphorylation, diseases caused by mutations in such genes affect organs most dependent on oxidative phosphorylation (skeletal muscle, hea, brain). Leber hereditary optic neuropathy is the prototypical disorder in this group. This neurodegenerative disease manifests itself as progressive bilateral loss of central vision that leads in due course to blindness. Prader-Willi and Angelman Syndromes- Diseases Caused by Alterations of Imprinted Regions (Robbins Basic Pathology, 9 th edition. page : 243)