S1 Text. Patient recruitment and phenotypes (https://doi.org/10.1371/journal.pone.0304528.s001) (DOCX)

S1 Fig. Box-Cox normality plot showing the correlation coefficient (maximum value at -0.14). (https://doi.org/10.1371/journal.pone.0304528.s002) (TIF)

S2 Fig. Principal component analysis with first two axes used for exclusion of case and control samples (1000 Genome data used as European ancestry control). (https://doi.org/10.1371/journal.pone.0304528.s003)(TIF)

S3 Fig. Principal component featuring distribution of samples in terms of country of origin. (https://doi.org/10.1371/journal.pone.0304528.s004) (TIF)

S4 Fig. Regional association plot at PRNP locus for conditional analysis on SNP rs1799990 with duration as phenotype (heterozygous model). (https://doi.org/10.1371/journal.pone.0304528.s005) (TIF)

S5 Fig. Regional association plot at suggestive locus (HDHD5) with duration as phenotype (additive model). (https://doi.org/10.1371/journal.pone.0304528.s006)(TIF)

S6 Fig. Regional association plot at suggestive FHIT locus with duration as phenotype (additive model). (https://doi.org/10.1371/journal.pone.0304528.s007) (TIF)

S7 Fig. Regional association plot at suggestive EREG locus with duration as phenotype (additive model). (https://doi.org/10.1371/journal.pone.0304528.s008) (TIF)

S8 Fig. Regional association plot at suggestive NEDD4 locus with age as phenotype (additive model). (https://doi.org/10.1371/journal.pone.0304528.s009) (TIF)

S9 Fig. Regional association plot at suggestive UGGT2 locus with age as phenotype (additive model). (https://doi.org/10.1371/journal.pone.0304528.s010) (TIF)

S10 Fig. Meta-analysis of case-only and case-control GWAS. (https://doi.org/10.1371/journal.pone.0304528.s011) (TIF)

S11 Fig. Power analysis indicating the strength of power of PRNP lead SNP (rs1799990) and lead SNPs of suggestive hits as described in the Results section based on a range of effect sizes vs. MAF. (https://doi.org/10.1371/journal.pone.0304528.s012) (TIF)

S12 Fig. Histograms for phenotype age before and after Box-Cox transformation for codon 129 genotypes MM, MV and VV. (https://doi.org/10.1371/journal.pone.0304528.s013) (TIF)

S13 Fig. Histograms for phenotype duration before and after Box-Cox transformation for codon 129 genotypes MM, MV and VV. (https://doi.org/10.1371/journal.pone.0304528.s014) (TIF)

S1 Table. List of 53 significantly associated SNPs (Pvalue < 5x10-8). (https://doi.org/10.1371/journal.pone.0304528.s015) (XLSX)

S2 Table. List of 51 suggestively associated SNPs (5x10-8 > Pvalue < 1x10-5). (https://doi.org/10.1371/journal.pone.0304528.s016) (XLSX)

S3 Table. Top 10 genes identified by MAGMA (standalone) gene analysis (including genome-wide significant SNPs) with age as phenotype. (https://doi.org/10.1371/journal.pone.0304528.s017) (XLSX)

S4 Table. Top 10 genes identified by FUMA gene analysis (including genome-wide significant SNPs) with age as phenotype. (https://doi.org/10.1371/journal.pone.0304528.s018) (XLSX)

S5 Table. Top 10 pathways identified by MAGMA (standalone) gene-set analysis (including genome-wide SNPs) using age as phenotype. (https://doi.org/10.1371/journal.pone.0304528.s019) (XLSX)

S6 Table. Genetic correlation using LDSC with a genetic correlation of 0.1467. (https://doi.org/10.1371/journal.pone.0304528.s020) (XLSX)

S7 Table. Top 10 genes identified by MAGMA involved in sphingolipid and intracellular trafficking pathways (including genome-wide significant SNPs) with age as phenotype. Green rectangles indicate genes involved in neurological diseases (PrD = Prion Disease, PD = Parkinson’s Disease, AD = Alzheimer’s Disease, ALS = Amyotrophic Lateral Sclerosis; HD = Huntington’s Disease, FTD = Frontotemporal Dementia) (NSNPS = number of SNPs annotated to a gene; N = number of samples; ZSTAT = Z-score for the gene, based on its p-value). (https://doi.org/10.1371/journal.pone.0304528.s021) (XLSX)

S8 Table. Top 10 genes identified by MAGMA involved in sphingolipid and intracellular trafficking pathways (including genome-wide significant SNPs) with duration as phenotype. Green rectangles indicate genes involved in neurological diseases (PrD = Prion Disease, PD = Parkinson’s Disease, AD = Alzheimer’s Disease, ALS = Amyotrophic Lateral Sclerosis; HD = Huntington’s Disease, FTD = Frontotemporal Dementia). (NSNPS = number of SNPs annotated to a gene; N = number of samples; ZSTAT = Z-score for the gene, based on its p-value). (https://doi.org/10.1371/journal.pone.0304528.s022) (XLSX)

S9 Table. Top 10 pathways identified by FUMA gene-set analysis (including genome-wide SNPs) using age as phenotype. (NGENES = number of genes in the gene-set dataset; BETA = regression coefficient of the gene set). (https://doi.org/10.1371/journal.pone.0304528.s023) (XLSX)