GLB1 and GM1 gangliosidosis: By 1980, several articles were published describing patients with low acid beta‐galactosidase activity but varying clinical presentations.10, 11, 12, 13 Also, Hans Galjaard and coworkers reported that when cultured cells from certain patients with “GM1 gangliosidosis” were grown together and chemically fused there was an increase in acid beta‐galactosidase activity showing genetic complementation.14 This laboratory had diagnosed a juvenile patient with low (about 10% of normal) beta‐galactosidase activity in leukocytes and cultured skin fibroblasts.