Despite the absence of a C. elegans ortholog of HTT, several groups have generated transgenic animals expressing polyQ tracts and human HTT fragments with varying polyQ-repeat lengths in different neuronal subtypes to study HD pathology (Satyal et al., 2000; Parker et al., 2001; Morley et al., 2002; Nollen et al., 2004). The gene discussed is HTT; the disease is Huntington disease.