Gene, genetics and genetic medicines in gastroenterology: Current status and its future

Table 9 Pharmacogenetics in gastrointestinal disorders[90-100]

Disorder	Gene	Drug(s)	Clinical impact	Ref.
CRC, gastric, pancreatic cancers	DPYD	5-fluorouracil, capecitabine	Deficiency life-threatening toxicity (mucositis, myelosuppression)	De Moraes et al[90]; Ruzzo et al[91]
CRC, pancreatic cancer	UGT1A1	Irinotecan	UGT1A1 28/28 reduced glucuronidation increased toxicity (neutropenia, diarrhea)	Maitland et al[92]
IBD, autoimmune hepatitis	TPMT/NUDT15	Azathioprine, 6-MP	TPMT or NUDT15 deficiency risk of myelosuppression	Moriyama et al[93]
IBD	HLA-DQA102:01, HLA-DQB102:02	Thiopurines	Increase risk of thiopurine-induced pancreatitis	Ås et al[94]
IBD	HLA-DQ2	Infliximab	Increased formation of antibody formation against infliximab	Brun et al[95]
GERD, H. pylori, ulcers	CYP2C19	PPIs (omeprazole, lansoprazole)	Poor metabolizers increase drug levels; rapid metabolizers treatment failure in H. pylori	El Rouby et al[96]
NAFLD, metabolic syndrome	SLCO1B1	Statins (e.g., simvastatin)	Variants statin-induced myopathy risk	SEARCH Collaborative Group[97]
IBD	ABCB1	Various (e.g., corticosteroids)	Associated with glucocorticoid resistance in some patients	Li et al[98]
Autoimmune hepatitis, liver transplant	CYP3A5	Tacrolimus	Expressors need higher doses; non-expressors risk overexposure	Kim et al[99]
IBD	G6PD deficiency	Sulfasalazine, dapsone	Increase risk of hemolysis	Dore et al[100]

CRC: Colorectal cancer; IBD: Inflammatory bowel disease; GERD: Gastroesophageal reflux disease; H. pylori: Helicobacter pylori; NAFLD: Non-alcoholic fatty liver disease; PPI: Prot on pump inhibitor.