A 10-year-old boy presented with priapism of 10 h duration which after unsuccessful conservative measures, was relieved by a saphenocorporeal shunt. A 4-year history of intermittent vague aching of fingers and toes accompanied by low-grade fever was reported. Fabry disease was confirmed by the lack alpha-galactosidase activity in serum and leucocytes. Other characteristic features of Fabry disease were not present. The condition was also diagnosed in his 14-year-old brother and suspected in his maternal grandfather who died at the age of 49 from renal failure of unknown aetiology.