A case of typical Noonan syndrome (NS) with eye abnormalities, pterygium colli, cryptorchid testes, lymphoedema and asymmetrical cardiac septal hypertrophy is reported in a 8-month old infant. This case was particularly interesting since it included skin manifestations which enabled an early diagnosis to be made. Ulerythema ophryogenes has already been proposed as a cutaneous marker of NS, but the keratinization disorders in our patient also included disseminated keratosis of both hair follicles and sweat glands orifices. Abnormally brittle short curly hair has already been reported, but our patient exhibited progressive alopecia which is very rare in NS. Biochemical hair analysis did not show any abnormalities of aminoacids. All these features were suggestive of keratosis follicularis spinulosa decalvans. It therefore seems very likely that NS is associated with keratinization disorders but ulerythema ophryogenes might only be the limited form of these disorders. The other skin manifestations of NS are reviewed. Since the patient had 4 "café au lait" spots, the relation of NS with Von Recklinghausen syndrome, and neurofibromatosis-Noonan syndrome is discussed. Watson's Leopard and cardio-facial syndromes overlap with, and may represent subsets of NS.