POLG and chronic atrial and intestinal dysrhythmia: For instance, CIPO symptoms can manifest as a result of recessive mutations in important mitochondrial genes (TYMP, POLG) [86, 87]; can be caused by mutations in SGOL1 in chronic atrial and intestinal dysrhythmia (CAID) [88]; and mutations in the ACTG2 gene in megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) [89].