We showed a linear relationship between the number of CAA interruptions and overall repeat length. Furthermore, we showed that the prevalence of alleles with three CAA interruptions (characteristic of the disease-causing alleles) is most common in African and South Asian genetic ancestries.

We identified expanded repeats in four individuals with learning difficulties without ataxia and in three individuals in UK Biobank, one with hereditary ataxia (also highlighted by Fearnley et al. (2024)), one with hereditary neuropathy, and one with neurodegenerative disease. See an exemplary case:

We explored the repeat size and structure by interrogating data from from Genomics England, the UCL Queen Square Institute of Neurology in-house database (UCL IoN), and the UK Biobank.