Loss-of-function mutations in the progranulin (GRN) gene cause neurological disease in patients, typically frontotemporal lobar degeneration (FTLD) for heterozygous-null mutations [1, 2], and neuronal ceroid lipofuscinosis (NCL) in the rare case of homozygous-null mutations [3]. The gene discussed is GRN; the disease is neuronal ceroid lipofuscinosis.