20th July 2023

Pathophysiology

HD is inherited in an autosomal dominant manner, although 10% of cases are due to a de novo mutation. A mutation in the HTT gene located on the short arm of chromosome 4 leads to the expansion of the CAG trinucleotide segment. This leads to patchy neuronal loss in the cerebellum, occurring predominantly in the basal ganglia. HD demonstrates a phenomenon known as genetic anticipation; this means that each subsequent generation tends to experience symptoms at an earlier age.