Single sperm analysis of the trinucleotide repeats in the Huntington's disease gene: quantification of the mutation frequency spectrum Authors: Esther P.Leeflang, Lin Zhang, Simon Tavaré, Rene Hubert, Jayalakshmi Srinidhi, Marcy E.MacDonald, Richard H.Myers, Margot de Young, Nancy S.Wexler, James F.Gusella and Norman Arnheim