Clinical and genetic heterogeneity in early onset cerebellar ataxia with retained tendon reflexes.

Early onset cerebellar ataxia with retained reflexes: a clinical and genetic conundrum

“…The most significant clinical findings, in addition to autosomal recessive inheritance and consanguinity in 50% of cases, were cerebellar ataxia with dysarthria, retained reflexes associated or not with peripheral neuropathy and cerebellar atrophy on brain magnetic resonance imaging (MRI) 7 . Harding described EOCARR as being the second most common form of ARCA after FA, a similar finding to that reported by Filla et al In a review of ARCA, Palau and Espinós noted that EOCARR is the third most common form of ARCA after AF and ataxia telangiectasia [2][3][4] . Interestingly, none of the reviews of ARCA published in the last two years even References mention a diagnosis of EOCARR 8,9 .…”

“…Other forms of ARCA are much less common . EOCARR then became considered a differential diagnosis for FA and its variants such as Friedreich ataxia with retained reflexes (FARR) [1][2][3][4][5] . The main point of discussion regarding FA and EOCARR concerns their genetic differences: whereas the genetic cause of FA has been defined (the presence of a GAA triplet repeat expansion in the first intron of the FA gene, on the proximal long arm of chromosome 9), the genetic cause of EOCARR remains unknown, and to date there has only been one study of the condition (in a Tunisian family), in which a locus on chromosome 13q11-12 was identified, but not the causative gene 1,3,6 .…”

Clinical spectrum of early onset cerebellar ataxia with retained tendon reflexes: an autosomal recessive ataxia not to be missed

“…The demonstration of cerebellar atrophy in the majority of EOCA patients supported the view that EOCA was distinct from FA 9 . Additionally, some data also has demonstrated that EOCA is characterized by a heterogeneous progression 11,12 . Although past decade has seen great advances in unraveling the biological basis of hereditary ataxias, knowledge on the genetic features of EOCA is still extremely restricted.…”

Autosomal recessive cerebellar ataxias

“…More EOCARR cases have been reported later [182][183][184]. Chio et al [185] described 40 cases diagnosed between 1940 and 1990 in a defined area of North-western Italy.…”

“…EOCARR is one of the most frequent autosomal recessive ataxias (after Friedreich ataxia and A-T): the estimated point prevalence ratio is 1/ 100,000 population and the birth incidence rate is 1/ 48,000 live births. Current data suggest that it is, in fact, a heterogeneous disorder characterized by early onset cerebellar ataxia (in the first or second decade of life) with preservation of deep tendon reflexes [186,187].…”