The knowledge that he had passed the disease onto his children would have tortured him. The shaker mutant rat, originally present in Sprague Dailey outbred stock, is an excellent animal model for anatomical and movement analysis studies of hereditary cerebellar ataxia. Anatomical studies have demonstrated a progressive loss of Purkinje cells and precerebellar inferior olivary neurons. Onset of Purkinje cell degeneration begins approximately six to eight weeks postnatally. Clinically, the shaker presents with wide hindlimb stance, gait ataxia, and tremor.
Movement deteriorates as the neurodegeneration advances.
The National Ataxia Foundation funded the initial endeavors to develop a congenic strain of the Shaker mutant. Breeding continues to develop a congenic strain of the shaker mutant onto a Wistar strain background. Development of a congenic strain onto a Lewis rat strain background has been unsuccessful. Many breeding pairs were infertile. The clinical sign of tremor was not present in female offspring of fertile intercross pairs as expected with a sex-linked mode of inheritance.