The same type of analysis using 26 biopsies of control and patients affected of NCL according to the expression pattern of PYGM, GPD1 and β-F1/LDH-A ratio resulted in their distribution into two different groups, control donors and NCL patients, with a high sensitivity (100%) and specificity (85%) (Figure 3C). The gene discussed is GPD1; the disease is neuronal ceroid lipofuscinosis.