Chapter 11 Metabolic Causes of Ataxia

Abstract

Publisher Summary A variety of metabolic insults can result in cerebellar dysfunction and ataxia. This chapter discusses diseases that are related to the defects of mitochondrial function and various metabolic pathways. It discusses chronic progressive external ophthalmoplegia (CPEO) and Kearns–Sayre syndrome (KSS), encephalomyopathies, neurogenic weakness ataxia and retinal pigmentation (narp), Leigh syndrome (LS), Friedreich's ataxia (FRDA), twinkle mutations, and polymerase gamma mutations. CPEO is predominantly a myopathic disorder, but there have been reports of dementia, seizures, myoclonus, and stroke-like episodes. In a study of 66 patients, there was mild limb or gait ataxia in 41%. The common mitochondrial encephalopathies include myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and myoclonic epilepsy and ragged red fibers (RRFs) (MERRF). MELAS can include psychomotor retardation, ataxia, cognitive impairment, deafness, diabetes mellitus, and limb weakness. NARP are peripheral neuropathy, ataxia, retinitis pigmentosa, seizures, and dementia. LS is a subacute necrotizing encephalomyelopathy characterized by bilateral symmetric focal necrotic lesions within the thalamus and extending into the pons, inferior olives, and spinal cord. FRDA is an autosomal recessive disease characterized clinically by a progressive gait and limb ataxia, absence of deep tendon reflexes, and the loss of position and vibration sense in the lower limbs.