Molecular basis of Huntington Disease: CAG repeat

(CAG) repeats in the HD gene locus lead to runs of Glutamine (Gln) in HD protein. Onset and severity are correlated with the number of repeats, with variable penetrance beginning at ca. 40 repeats.

Figure © 2012 TA Brown, Introduction to Genetics (1st ed.); additional text ©2014 by Steven M. Carr