Table 1.- Variants (SNPs) included in the PRS calculation
(Disease/Trait: Arthritis_juvenile_idiopathic)
rsID	Risk allele	Effect size
rs4688011	A	0.207
rs12719740	A	0.140
Effect size: LN(OR)

Table 2.- PRS Score distribution among populations and regions
(Disease/Trait: Arthritis_juvenile_idiopathic)
	count	mean	sd	se	lower.ci	upper.ci
Pyrenean regions
WEST	168	0.030	0.034	0.003	0.025	0.036
SOUTH	83	0.034	0.036	0.004	0.026	0.042
EAST	146	0.036	0.040	0.003	0.029	0.042
Populations
IBS	107	0.042	0.042	0.004	0.034	0.050
PIR	397	0.033	0.037	0.002	0.030	0.037

Table 3.- Pairwise t-test for PRS score among populations and regions
(Disease/Trait: Arthritis_juvenile_idiopathic)
group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
IBS	PIR	107	397	0.0264	*	0.264	ns
IBS	WEST	107	168	0.0101	*	0.101	ns
IBS	SOUTH	107	83	0.1470	ns	1.000	ns
IBS	EAST	107	146	0.1780	ns	1.000	ns
WEST	SOUTH	168	83	0.4270	ns	1.000	ns
WEST	EAST	168	146	0.1940	ns	1.000	ns
SOUTH	EAST	83	146	0.7670	ns	1.000	ns
* p < .05, ** p < .01, *** p < .001

Table 4.- Chi-square test comparison of percentile counts on Pyrenean regions compared to Iberian peninsula population
(Disease/Trait: Arthritis_juvenile_idiopathic)
Percentile rank	PIR				WEST				SOUTH				EAST
	adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val		adj.std.val	p.value	sig.val
pct95	−0.900	0.368	.	white	−2.050	0.040	*		−0.900	0.368	.	white	−0.350	0.726	.	white
pct75.95	−0.270	0.787	.	white	−1.450	0.147	.	white	−0.270	0.787	.	white	−1.110	0.267	.	white
pct50.75	−0.770	0.441	.	white	0.430	0.667	.	white	−0.770	0.441	.	white	−0.040	0.968	.	white
pct25.50	0.680	0.497	.	white	−0.230	0.818	.	white	0.680	0.497	.	white	−0.130	0.897	.	white
pct25	0.670	0.503	.	white	1.670	0.095	.	white	0.670	0.503	.	white	1.140	0.254	.	white
adj.std.val: Adjusted standardized residuals value; p.value: P value; sig.val: statistical significance, * p < .05, ** p < .01, *** p < .001; red dash to bottom: lower counts than reference; green dash to up: upper counts than reference