MILD PHENOTYPIC-EXPRESSION OF ALPHA-N-ACETYLGALACTOSAMINIDASE DEFICIENCY IN 2 ADULT SIBLINGS

Two adult siblings with an alpha-N-acetylgalactosaminidase deficiency are described. The patients' major features are massive lymphoedema an d angiokeratoma corporis diffusum. Neurological evaluation performed i n one of the patients was considered within normal limits. Blood type is A positive in each case. Ultrastructural examination of skin reveal ed numerous vacuoles in endothelial cells and pericytes. Fibroblast ac tivity of alpha-N-acetylgalactosaminidase was decreased to 0.6-2% of m ean normal value. Chromatography of urinary oligosaccharides showed ab normal bands identical to those excreted by two infantile patients wit h Schindler disease. The bands were identified as sialyloligosaccharid es, and gas chromatography revealed the presence of N-acetylgalactosam ine-rich compounds accounting for 30% of the total monosaccharide cont ent of the oligosaccharide fraction. These findings confirm the hetero geneity of alpha-N-acetylgalactosaminidase deficiency and emphasize th e need to consider this lysosomal storage disease in the differential diagnosis of patients with angiokeratoma.