Synthetic datasets to mimic the repeat architecture of the HTT gene

Synthetic datasets were generated with 10,000 simulated sequencing reads to mimic the repeat architecture of the HTT gene. Each read was constructed to represent HTT exon 1, including variable-length CAG and CCG repeat tracts and a defined loss-of-interruption (LOI) pattern at the CAG–CCG junction.CAG repeat sizes were drawn from two Gaussian distributions centered on typical alleles (default means: 17 and 49 repeats) with a default standard deviation of 2. To increase allelic variability, an extra subset of CAG lengths was uniformly sampled between 10 and 100 repeats. All simulated CAG values were then constrained to the 1–100 repeat interval.CCG repeat lengths were assigned independently, sampled from two fixed values (default: 7 and 10 repeats). Finally, six distinct LOI scenarios were introduced, representing both reported and hypothetical interruption patterns at the interface between the CAG and CCG tracts.