Hereditary Progressive Dystonia with marked diurnal fluctuation (HPD) is an autosomally dominantly inherited dystonia which is characterized by marked diurnal fluctuation of symptoms and by marked and sustained response to levodopa associated with mutations in guanosine triphosphate cyclohydrolase (GCH-1) deficiency gene. We report an italian patient with a new 18 bp deletion at 267 in exon 1 in the GCH-1 gene. The peculiarity of our patient is the new mutations never reported and mnemonic disturbances that are also not reported in the classical HPD.A genotype-phenotype relationship may be suggested between different gene mutations and non classical clinical manifestations.