INS and congenital isolated hyperinsulinism: While non-genetic forms of HI in neonates are transient, caused mostly by perinatal stress, or a mother’s uncontrolled diabetes, CHI is monogenic and can present either as an isolated CHI due to a variant in a gene directly involved in insulin secretion or as a syndromic CHI, such as Kabuki, Turner or Beckwith-Wiedemann syndromes.