Twin research shows glycan changes are more susceptible to environmental factors than their carrier glycoproteins.

Changes in protein glycosylation are clinically used as biomarkers. In the present study, we employed a twin cohort to investigate the contributions of genetic and environmental factors to glycan modifications of glycoproteins. Mac-2 binding protein (Mac-2 bp), haptoglobin (Hp), and their glycosylated forms are liver fibrosis and cancer biomarkers. Sera from 107 twin pairs without clinical information were used as a training cohort for the Mac-2 bp and Mac-2 bp glycosylation isomer (M2BPGi) assay. As a validation cohort, 22 twin pairs were enrolled in the study. For each twin pair, one twin was diagnosed with liver or pancreatic disease. For the training cohort, the correlation ratios of serum Mac-2 bp and M2BPGi levels in twin sera with random sequences were 0.30 and 0.018, respectively. The correlation ratios between twin pairs in the validation cohort for serum Mac-2 bp and M2BPGi levels were 0.75 and 0.35, respectively. In contrast, correlation ratios of serum Hp and fucosylated haptoglobin (Fuc-Hp) levels between twin sera with liver and pancreatic disease were 0.49 and 0.16, respectively. Although serum protein levels of glycoproteins are susceptible to genetic factors, characteristic glycan changes of these glycoproteins are more susceptible to environmental factors, including liver and pancreatic disease.