Examination of whole-mount mammary glands from virgin female MMTV-PyVT/HdhQ111/Q111 mice at 8, 12 and 14 weeks (Fig 1B) revealed larger mammary adenocarcinomas than in the huntingtin heterozygous condition, themselves larger than those produced in the wild-type background at the same age. The gene discussed is HTT; the disease is breast adenocarcinoma.