The co-occurrence of FTD and NCL within a family due to GRN mutations has been reported and provides the unique opportunity to investigate the genotype–phenotype correlations regarding GRN dosage effect; the homozygous relative displayed dysarthria, cerebellar ataxia, retinal dystrophy, and severe global cerebellar atrophy [140]. The gene discussed is GRN; the disease is neuronal ceroid lipofuscinosis.