Types of mitochondrial disease?

Mitochondrial disease can have many presentations because mitochondria are located everywhere within the body. The severity of damage, location, and number of mitochondria affected all have an affect on body functioning. So far we know of at least 100 different types of mitochondrial disease with the potential for 100s more. New presentations of this disease appear regularly.

Some mitochondrial disorders might only affect a single organ, such as the eye in Leber hereditary optic neuropathy (LHON), but most involve multiple organs, with the nerves and muscles being affected the most.

Many affected individuals will present with a number of features that fall into a discrete subgroup, such as the Kearns-Sayre syndrome (KSS), chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged-red fibres (MERRF), neurogenic weakness with ataxia and retinitis pigmentosa (NARP), or Leigh syndrome (LS).

 Others subgroups may be named according to the actual defect occurring in the mitochondria, such as COX deficiency or complex I and IV deficiency. However, many individuals will not fit neatly into any one particular subgroup. Also, the actual genetic hiccup will not be found in many cases.