Table 3 Genetic association of eight single nucleotide polymorphisms (SNPs) spread over collagen type III alpha I (COL3A1) in the Trio cohort and in the extended adult case–control cohort

Number	SNP	Gastro-oesophageal reflux disease					Hiatus hernia
		Trios, all	Trios, males		Case–control, all		Case–control, males
		p Value	p Value	p_corr	p Value	p_corr	p Value	p_corr
1	rs12693520	0.18	0.0167	0.08	0.85	1.00	0.45	0.95
2	rs6434304	0.042	0.0037	0.018	0.95	1.00	0.25	0.76
3	rs2056156	0.21	0.0913	0.37	0.068	0.31	0.04	0.19
4	rs3106798	0.30	0.11	0.42	0.028	0.14	0.09	0.40
5	rs7579903	0.055	0.023	0.12	0.0037	0.022	0.44	0.94
6	rs1800255	0.092	0.068	0.31	0.44	0.95	0.09	0.37
7	rs1040187	0.95	0.76	1,0	0.14	0.54	0.38	0.90
8	rs3134646	0.91	0.39	0,91	0.025	0.13	0.003	0.019

Only the males from the Trio cohort show significant genetic association for SNP number 2 after multiple testing adjustments with a p_corr of 0.018. There is no gender bias in the adult case control cohort. Significant association for GORD in the case–control cohort was identified for SNP number 5 with a p_corr of 0.022. COL3A1 is also associated with hiatus hernia in the adult case–control cohort. The associated SNP, number 8, has a p_corr of 0.019. The identified association is male specific. The patient overlap is 98 individuals, eg, having both GORD and hiatus hernia.