PTH and Alzheimer disease: The condition can be isolated (sporadic or familial with autosomal dominant (AD), autosomal recessive (AR), or X-linked recessive (XR) inheritance) or associated with mutations affecting parathyroid development genes, such as GCM2 (6p24.2) and SOX3 (2p25.3, Xq27.1), or PTH synthesis and secretion genes (prepro-PTH—11p15Congenital hypoparathyroidism is often a part of syndromic conditions such as DiGeorge syndrome (del.22q), HDR syndrome (AD), Kenny–Caffey syndrome, Sanjad–Sakati syndrome (1q42-q43), or mitochondrial DNA-related conditions such as Kearns–Sayre syndrome and MELAS [2].