In this context, it has been shown that an excessive Rho activity, negatively affects synaptic and cognitive functions [42] and errors in cellular modulators of APP processing induced by polymorphisms (such as the apoE4 ε-allele) predisposes an individual to early or late-onset AD induced by an hyper-activation of the Rho family GTPases [43]. The gene discussed is RHO; the disease is Alzheimer disease.