Friedreich’s ataxia (FXN expansions)
Spinocerebellar ataxia by expansion
The prevalence of spinocerebellar ataxia (SCA) in the general population is estimated to be 2.7 per 100,000 individuals (Ruano et al., 2014). Friedreich ataxia is the most common hereditary ataxia in Caucasians, with an estimated incidence of 1/29,000 individuals and a frequency of 1/85 carriers. Between 2% and 13% of late-onset and sporadic ataxia cases are caused by nucleotide expansions detected by specific PCR/TP-PCR studies (Abele et al., 2002). Anticipation, consisting of early-onset and/or more severe disease in subsequent generations, is a characteristic phenomenon of ataxias. Apart from testing for nucleotide repeat expansions, we have designed NGS panels for the detection of point variants and CNVs in genes responsible for SCA (SPG7, SETX, SACS, AFG3L2, or SYNE1, among others; Galatolo et al., 2017), which we offer structured according to the mode of inheritance (autosomal dominant or autosomal recessive).
- Abele M, Bürk K, Schöls L, Schwartz S, Besenthal I, Dichgans J, Zühlke C, Riess O, Klockgether T. The aetiology of sporadic adult-onset ataxia. Brain. 2002 May;125(5):961-8.
- Galatolo D, Tessa A, Filla A, Santorelli FM. Clinical application of next generation sequencing in hereditary spinocerebellar ataxia: increasing the diagnostic yield and broadening the ataxia-spasticity spectrum. A retrospective analysis. Neurogenetics. 2018 Jan;19(1):1-8.
- Ruano L, Melo C, Silva MC, Coutinho P. The global epidemiology of hereditary ataxia and spastic paraplegia: a systematic review of prevalence studies. Neuroepidemiology. 2014;42(3):174-83.