MRCP revision battle 46.3: Mitochondrial disorders and Leber's Optic Atrophy

mDNA mutates 10x more frequently than normal DNA.  However, there is a poor genotype to phenotype correlation so the mutations are often not noticed.


Since sperm do not contain mitochondria mitochondrial disorders are passed exclusively from mother to child.


The most famous mitochondrial disorders are:

1. Kearns Sayre - see battle 15.5
2. Leber's hereditary optic neuropathy.
3. Some forms of sensorineural deafness

Leber's hereditary optic neuropathy

• mDNA mutation
• progressive loss of central vision due to optic atrophy, begins in young adulthood
• if LHON 'plus' also:
• multiple-sclerosis type symptoms
• Wolff-Parkinson White

Next up - some cytotoxic agents (which sadly sounds more exciting than it is)