HEXA and Tremor: Independently, Seyrantepe et al. [80] conducted a thorough phenotypic characterization of double-knockout Hexa−/-Neu3−/− mice and determined that, in contrast with Hexa−/− mice that had a late onset at 10–11 months, the double-KO mice showed rapid deterioration with slow movement, ataxia and tremors and had a life span of only 1.5 to 4.5 months, similar to that of the Sandhoff Hexb−/− mice.