The genetics of Huntington's disease are complex and non-Mendelian, characterized by intergenerational enlargement of CAG repeats.

“it's actually the the genetics of it are real interesting because they are non-mendelian because the length of the cag repeat actually changes intergenerationally the weird thing about it is there's there's these cag repeats that code for polyglutamines polyglutamine stretches in the protein they are unstable in replication and so what you tend to see is an enlargement of these polyglutamine repeats from one generation to the next and so — yeah so it has this really weird — non-mendelian pattern”