Update on Mitochondrial Disorders
by Beth A. Pletcher, MD, March 2000

Common Manifestations:

  • Elevated lactate; abnormal urine organic acids

  • Neuropathy; myopathy

  • Static encephalopathy

  • Fatigue, muscle cramps, intermittent pedal edema, temperature instability or cyclic vomiting

  • Family history of migraines, seizures, learning disabilities, GI dysmotility or SIDS

Table of Some Well Defined Mitochondrial Disorders

Manifestation
  
LHON
MELAS
MERRF
NARP
KSS

maternal family history

+

+

+

+

-

optic atrophy

 

+

-

-

-

-

ophthalmoplegia

 

-

-

-

-

+

retinitis pigmentosa

 

-

-

-

+

+

myoclonic seizures

 

-

-

+

+

+

other seizures

 

-

+

+

+

+/-

ataxia

 

-

-

+

+

+

myopathy

 

-

+

+

+

+

neuropathy

 

-

+/-

+/-

+

-

encephalopathy

 

-

+

+

+

+

sensorineural hearing loss

 

-

+

+

+

+

lactic acidosis

 

-

+

+

+/-

+

ragged red fibers

 

-

+

+

+

+

LHON= Leber's hereditary optic neuropathy
MELAS= Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes
MERRF= Myoclonic epilepsy, elevated lactic acid and ragged red fibers
NARP= Neuropathy (sensory), abnormal development (developmental delay) and retinitis pigmentosa
KSS= Kearns-Sayre syndrome

Available Treatment Modalities for Mitochondrial Disorders

  • Carnitine; Coenzyme Q 10

  • Dichloroacetate for lactic acidosis

  • Multivitamin cofactors; Vitamins E, C, K; Riboflavin; Folinic acid

  • Avoidance of fasting with frequent meals