Notably, a patient with PT, who had only two copies of the APP gene and showed no evidence of cognitive decline in late life or AD pathology at post‐mortem exam,29 showed Rab activities and CCZ1 and SH3BP5 levels comparable to cognitively normal controls (Figure S4), supporting a role for increased APP gene dose involvement in observed changes. The gene discussed is SH3BP5; the disease is Alzheimer disease.