Blood groups B and P1 are substrates for the lysosomal enzyme alpha-galactosidase A. Therefore, patients with alpha-Gal A deficiency and blood groups B or P1 may exhibit more severe disease. In 48 Fabry patients distribution of blood group was not different from that in the Dutch population. No patient had blood group B. Clinical symptoms did not differ between bloodgroup P1 or P2 patients. We conclude that blood groups B and P1 are not overrepresented in Dutch Fabry patients. Blood group P1 is not correlated with more severe disease and cannot be considered a significant risk factor.