MITOCHONDRIAL DNA DISORDERS
Mitochondrial DNA codes
for mitochondrial oxidative phosphorylation enzymes;inheritance is only from
mother to child, because only the ovum contributes mito-chondria to the zygote.
Leber hereditary optic neuropathy causes
loss of retinal cells, which leads tocentral vision loss.
Myoclonic epilepsy with ragged red fibers (MERRF) is
a mitochondrial disor-der characterized by epilepsy, ataxia, peripheral
neuropathy and deteriora-tion in cognitive ability. Sensorineural hearing loss
and ocular dysfunction can also develop. Patients have short stature and
cardiomyopathy. On muscle biopsy, ragged red fibers are seen on Gomori
trichrome staining due to the accumulation of mitochondria.