. "repeat expansion of the trinucleotide sequence CAG" . . . "repeat-expanded" . . . "Trinucleotide repeat expansion" . "nucleotide repeat expansion mutations" . "expansion" . "Trinucleotide repeats may expand" . . "CTG triplet expansion" . "Repeat expansion" . . . "trinucleotide repeat" . . "Trinucleotide CAG repeats" . "Trinucleotide repeat expansion" . "trinucleotide repeat expansion" . .