β-galactosidase deficiency in Colombia: Report of 20 patients detected using dried blood spot samples

Abstract

β-Galactosidase (BGal) is the first enzyme involved in the catabolism of sphingolipids. Two pathologies have been directly associated with its deficiency:GM1 gangliosidosis andMorquio B. Morquio B is among the rarest types of mucopolysaccharidosis (MPS).We aim to document the β-galactosidase deficiency in Colombia. We evaluated leukocytes from 1492 healthy Colombian individuals and 923 patients, referred between 2005 and August 2014. Dried blood spot (DBS) samples from the same number of patients were evaluated. β-Galactosidase was measured with 4-methylumbelliferyl-β-D-galactoside. As a control enzyme, the total hexosaminidase activity was also evaluated. We identified 14 patients with GM1 gangliosidosis, 5 patients with Morquio B, and 1 patient with I-cell disease. We could establish a reference value for Bgal in Colombian leukocyte samples. GM1 gangliosidosis is the main pathology associated with a direct deficiency of BGal. The high number of patients found with MPS IVB indicates that there are patients who could be misdiagnosed due to an unawareness of the disease.