Dosage of PGRN plays a central role in its cellular functions as haploinsufficiency of PGRN leads to an adult-onset neurodegenerative disorder, frontotemporal lobar degeneration (FTLD-TDP-Pgrn), while complete loss of PGRN leads to a childhood lysosomal storage disorder called neuronal ceroid lipofuscinosis (NCL) [3–5]. The gene discussed is GRN; the disease is neuronal ceroid lipofuscinosis.