It is notable that genes ESR1, ESR2 and PTGS2 are shared across Alzheimer’s disease (BRCA1, PTGS2, ESR1, ESR2, BCL2 and CSF1) and Parkinson’s disease (ESR1, ESR2 and PTGS2), suggesting that they are involved in shared molecular mechanisms of neurodegeneration and inflammation in the two neurological disorders. The gene discussed is PTGS2; the disease is early-onset autosomal dominant Alzheimer disease.