CHIT1 and early-onset autosomal dominant Alzheimer disease: Chit1 has attracted considerable attention due to its increased expression in individuals with different pathological conditions such as Gaucher disease [9], chronic obstructive pulmonary disease (COPD) [18], Alzheimer’s disease [19], atherothrombosis [20], diabetes mellitus [21] cystic fibrosis [22] as well as in smokers [23].