Urinary coproporphyrin excretion in Rotor's syndrome: a family study

A family of seven is described in which a teenage boy and two siblings were found to have Rotor's syndrome. Total urinary coproporphyrin excretion was found to be significantly elevated in the patients with Rotor's syndrome (mean 59 . 0 mumol/mol creatinine), when compared with control subjects (mean 16 . 3 mumol/mol creatinine) (p less than 0 . 005). Similarly, urinary excretion of both coproporphyrin isomer I and coproporphyrin isomer III was greater in the subjects with Rotor's syndrome than in controls (p less than 0 . 005). Coproporphyrin I comprised 60 . 2% of total urinary coproporphyrin excretion in the subjects with Rotor's syndrome, compared with 38 . 6% in the controls, but the difference was not significant. In the parents and clinically unaffected siblings neither total urinary coproporphyrin excretion (13 . 3 and 19 . 3 mumol/mol creatinine respectively) nor percentage coproporphyrin I excretion (36 . 8 and 30 . 4%) differed from controls. Thus, although we have confirmed the previous finding of increased urinary coproporphyrin excretion in subjects with Rotor's syndrome, we have not found the previously noted intermediate increase in coproporphyrin I excretion amongst phenotypically normal relatives of subjects with this autosomal recessive disorder.