Table 1.

Overview of genetic association studies in achalasia

Protein (gene)	Polymorphism	Finding	Ref.
PTPN22	C1858T	Risk factor	[28]
IL-10	GCC	Protective	[29]
IL-23R	G381A	Protective	[30]
iNOS	iNOS22*A/A	No association	[35]
eNOS	eNOS*4°4°	No association	[35]
iNOS	(CCTTT) n > 12	Risk factor	[36]
cKit	Rs6554199	Risk factor	[37]
VIPR type 1	Rs437876 and rs896	Risk factor	[38]

iNOS: Inducible nitric oxide synthase; IL: Interleukin; PTPN22: Polymorphism C1858T of phosphatase N22.