Generally, loss of sialic acid on an array of glycopeptides was associated with disease, except that in HD patients, HDL was enriched in di-sialylated ApoC-III isoform (ApoC-III2) and depleted in the less sialylated ApoC-III1 and ApoC-III0 isoforms. This evidence concerns the gene APOC3 and Huntington disease.