We report the case of a 77-year-old Caucasian man with severe dementia and behavioral disturbance secondary to Alzheimer’s disease treated with memantine who began adjunct treatment with deoxyribonuclease I. Prior to initiation of deoxyribonuclease I treatment, our patient appeared to be in a stuporous state, with a Mini-Mental State Examination score of 3 and a Functional Assessment Staging Test score of 7. Here, DNASE1 is linked to early-onset autosomal dominant Alzheimer disease.