Table 1.- Variants (SNPs) included in the PRS calculation
(Disease/Trait: Ossification_of_the_posterior_longitudinal_ligament_of_the_spine)
rsID	Risk allele	Effect size
rs2423294	A	0.344
rs374810	G	0.293
rs1979679	T	0.262
rs11045000	A	0.247
rs13279799	C	0.247
Effect size: LN(OR)

Table 2.- PRS Score distribution among populations and regions
(Disease/Trait: Ossification_of_the_posterior_longitudinal_ligament_of_the_spine)
	count	mean	sd	se	lower.ci	upper.ci
Pyrenean regions
WEST	168	0.103	0.039	0.003	0.097	0.109
SOUTH	83	0.104	0.042	0.005	0.095	0.113
EAST	146	0.097	0.041	0.003	0.091	0.104
Populations
IBS	107	0.095	0.037	0.004	0.088	0.102
PIR	397	0.101	0.040	0.002	0.097	0.105

Table 3.- Pairwise t-test for PRS score among populations and regions
(Disease/Trait: Ossification_of_the_posterior_longitudinal_ligament_of_the_spine)
group1	group2	n1	n2	p	p.signif	p.adj	p.adj.signif
IBS	PIR	107	397	0.176	ns	1	ns
IBS	WEST	107	168	0.105	ns	1	ns
IBS	SOUTH	107	83	0.138	ns	1	ns
IBS	EAST	107	146	0.713	ns	1	ns
WEST	SOUTH	168	83	0.900	ns	1	ns
WEST	EAST	168	146	0.175	ns	1	ns
SOUTH	EAST	83	146	0.215	ns	1	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: Ossification_of_the_posterior_longitudinal_ligament_of_the_spine)
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	1.820	0.069	.	white	1.250	0.211	.	white	1.820	0.069	.	white	1.660	0.097	.	white
pct75.95	0.270	0.787	.	white	1.300	0.194	.	white	0.270	0.787	.	white	−0.280	0.779	.	white
pct50.75	1.050	0.294	.	white	0.590	0.555	.	white	1.050	0.294	.	white	1.500	0.134	.	white
pct25.50	−1.350	0.177	.	white	−1.680	0.093	.	white	−1.350	0.177	.	white	−2.300	0.021	*
pct25	−0.610	0.542	.	white	−0.570	0.569	.	white	−0.610	0.542	.	white	0.300	0.764	.	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