Syndrome that is characterized by silvery to leaden hair, bronze skin color in sun-exposed areas and severe neurological impairment. The syndrome was first described in 1979 in three consanguineous families. It is either congenital or develops during childhood (seizures, severe hypotonia and intellectual deficit). There is no impairment of the immune system and a wide spectrum of ophthalmologic abnormalities has been described. Molecular data has shed light on the complex relationship that exists between this syndrome and Griscelli syndrome. Mutations in the myosin Va gene (MYOVA) result in the so-called Griscelli syndrome type 1. MYOVA encodes myosin Va, an actin-based motor protein important for the intracellular transport of organelles in melanocyte and neuronal cells. It is very likely that Griscelli syndrome type 1 corresponds to with this syndrome.