PVR and autosomal dominant cerebellar ataxia: Furthermore, while 77.3% (17 out of 22 patients) of cases with loss of FAS and/or PVR genes had a fatal outcome, only 18.9% (49 out of 258 patients) of SCA NB patients, carrying intact FAS and/or PVR genes, died at 5 years of follow-up (Table 3, Figure 4C).