Vacuolated lymphocytes are a feature of several metabolic diseases including CLN3 [2, 3, 10, 27, 45] and CLN11 [8], Pompe’s disease/adult acid maltase deficiency [2, 19, 36], GM1 gangliosidosis [2, 14, 15] and others as summarized by Anderson et al. [2]. The gene discussed is CLN3; the disease is GM1 gangliosidosis.