Cases in which AD is diagnosed in later life, beyond the age of 60, are referred to as sporadic AD (SAD), whereas in familial AD (FAD) patients develop AD symptoms at younger ages due to mutations in genes such as amyloid precursor protein (APP), presenilin-1 (PSEN1) and presenilin-2 (PSEN2) [2]. The gene discussed is PSEN1; the disease is Alzheimer disease.