Why has the slow development huntingtons disease lead to increased frequencies in population?

The slow development of Huntington's disease allows individuals to reach reproductive age and pass the mutated gene to their offspring before symptoms manifest, often in mid-adulthood. This means that carriers may unknowingly transmit the gene to the next generation, resulting in an increased frequency of the disorder in the population. Additionally, the relatively late onset provides a longer window for gene propagation, contributing to its prevalence.