Our study demonstrates that the PSMD9 SNPs rs74421874 (IVS3+nt460 G>A), rs3825172 (IVS3+nt437 C>T) and rs1043307/rs14259 (E197G A>G) studied are linked to primary insomnia in the Italian T2D families; it shows a trend towards linkage to sleep hours, with a trait heritability estimated to be circa 11%, and gene-trait heritability circa 25%. This evidence concerns the gene PSMD9 and type 2 diabetes mellitus.