Genetic polymorphism of glycine-rich β-glycoprotein (GBG) was studied in populations from northern and southern Italy, respectively. Gene frequencies were as follows: northern Italy (n = 431): GbS = 0.7675, GbF = 0.2049, GbS0.7 = 0.0127, GbF1 = 0.0139; southern Italy (n = 161): GbS = 0.7050, GbF = 0.2360, GbS0.7 = 0.0373, GbF1 = 0.0217. Comparison of these two populations with the Swiss population revealed a significant drift in gene frequencies from north to south. A new GBG phenotype, supposedly heterozygous, with a slow migrating F band and a regular S band in agarose electrophoresis was observed