Atypical expression of ß-galactosidase deficiency in a child with Hurler-like features but without neurological abnormalities

A 28-month-old child was found to have several clinical features of lysosomal storage diseases, including: coarse facies, hepatosplenomegaly, lumbar kyphosis due to hypoplastic beaked L1 and L2 vertebral bodies, vacuolated lymphocytes in blood smears and rare foamy hystiocytes in bone marrow. However, no signs of neurological or ocular abnormalities were detected. A beta-galactosidase deficiency was demonstrated in leukocytes and cultured skin fibroblasts, with a residual activity toward 4-methylumbelliferyl-beta-galactopyranoside ranging between 5 and 15% of the normal mean. Normal activities were found for several other lysosomal acid hydrolases. beta-Galactosidase activities in leukocytes and cultured skin fibroblasts from both parents were within the normal ranges. The patient seems to represent an atypical expression of acid beta-galactosidase deficiency, since his clinical picture does not exaclty correspond to that of either the two classical types of GM1-gangliosidosis or other atypical patients reported in the literature havining beta-galactosidase deficiency.