Primary and secondary ataxias

Abstract

Knowledge of primary ataxias has been growing rapidly in recent years. Here we review different forms of primary ataxia, including inherited forms, which are subdivided into congenital, autosomal recessive cerebellar ataxias, autosomal dominant cerebellar ataxias, episodic ataxias, X-linked ataxias, and mitochondrial ataxias, as well as sporadic ataxias and idiopathic degenerative ataxias. Secondary or acquired ataxias are also reviewed and the most common causes are discussed.

Non-progressive cerebellar ataxia with previous acute cerebellar injury of undetermined origin: a puzzling neurological disorder

“…Secondary, or acquired, ataxias result from a variety of exogenous or endogenous non-genetic causes, including those of a toxic (drug-induced cerebellar ataxia), paraneoplastic, immune-mediated, nutritional or infectious nature, as well as focal injury to the cerebellum 1 . Non-progressive cerebellar ataxias are a very rare, chronic neurological condition with different etiologies, including congenital cerebellar malformations (such as Joubert' s syndrome) and inherited neurometabolic disorders (such as GLUT1 deficiency).…”

“…Primary cerebellar ataxias are subdivided into sporadic and hereditary ataxias 1 . The latter include congenital ataxias (such as Joubert' s syndrome); autosomal recessive cerebellar ataxias (ARCAs), including Friedreich' s ataxia and ataxia telangiectasia; autosomal dominant cerebellar ataxias, also known as spinocerebellar ataxias (SCAs), such as SCAs type 1, 2, 3, 6, 7 and 10); episodic ataxias; X-linked cerebellar ataxias; and mitochondrial ataxias.…”

“…1 Idiopathic sporadic degenerative cerebellar ataxias include the cerebellar form of multiple system atrophy (MSA-C) and idiopathic late-onset cerebellar ataxias (ILOCA) 1 . Secondary, or acquired, ataxias result from a variety of exogenous or endogenous non-genetic causes, including those of a toxic (drug-induced cerebellar ataxia), paraneoplastic, immune-mediated, nutritional or infectious nature, as well as focal injury to the cerebellum 1 .…”

Otoneurological findings prevalent in hereditary ataxias

“…The SCA types 2, 3, 6, and 7 are related to unstable CAG repeat expansions in the respective gene, and are classified as polyglutamine disorders 1,12,13,14 . The SCA10 is caused by a repeat expansion of an ATTCT pentanucleotide, in the intron 9 of the gene located in the chromosome 22q13.3.…”

“…Within the group of SCAs, we highlight types 2, 3, 6, 7 and 10, which are of interest in this study. The most common clinical symptoms in SCAs present as gait and appendage ataxia (dysmetria, diadochokinesia in limbs, intentional tremors), dysarthria, nystagmus, ophthalmoplegia, dysphagia, hearing loss (in some patients), pyramidal signs, lower motor neuron syndrome, cognitive dysfunction, epilepsy, visual disturbances (pigmentary retinopathy), peripheral neuropathy, dementia and movement disorders (including parkinsonism, dystonia, myoclonus and chorea) 1,12 .…”