In striking contrast, Wnt1-Cre;Itpr1flox/flox mice began to show ataxia around postnatal day 9 (P9), and exhibited dyskinesia including opisthotonus, repetitive rigid posture, and tonic contractions of the neck and trunk as they grew beyond 2 weeks (Movie S1, and the footprint analyses shown in Figure 6B, left panel). This evidence concerns the gene WNT1 and cerebellar ataxia.