Although Noonan syndrome is quite prevalent, there is a general paucity in the description of psychological and psychiatric aspects. In the present paper a 19-year-old female patient with Noonan syndrome is described who presented with anxiety symptoms. Mutation analysis in PTPN11, the NS1 gene on chromosome 12q24, showed no abnormalities. A diagnosis of panic disorder without agoraphobia was established. Treatment with citalopram resulted in a gradual decline of anxiety symptoms. The psychological profile was characterized by a prominent alexithymia. The main conclusion is that patients with Noonan syndrome might have deficits in emotional adaptative functions. It is hypothesized that alexithymia is a key feature of the behavioural phenotype.