Tissue-specific and repeat length-dependent somatic instability of the X-linked dystonia parkinsonism-associated CCCTCT repeat
The length of a CCCTCT repeat within the SINE-VNTR-Alu retrotransposon associated with X-linked dystonia-parkinsonism (XDP) is inversely correlated with the age of disease onset. Here, the Wheeler lab investigated the instability of this repeat. Findings reveal:1) length-dependent and expansion-biased instability, with greater expansions in brain than in blood; 2) brain region-specific patterns of expansion that are broadly similar to those of the Huntington’s disease CAG repeat; 3) evidence that CCCTCT expansion propensity may be modified by local chromatin structure. The data support a role for CCCTCT somatic expansion underlying the rate of XDP onset.