Congenital Nonobstructive, Nonhemolytic Jaundice: Effect of Tin-Mesoporphyrin

Abstract

Tin-protoporphyrin (SnPP) and tin-mesoporphyrin (SnMP) have been proposed for the treatment of Crigler-Najjar (CN) disease type 1;1,2 in fact, both drugs moderate the hyperbilirubinemia to some extent.1,2 These compounds bind to heme oxygenase far more avidly than does heme itself, thus blocking access of the natural substrate to the binding site of the enzyme and inhibiting heme degradation and bilirubin production.3-5 Because these synthetic compounds do not contain iron and thus cannot bind oxygen, they cannot be oxidatively transformed into bilirubin by the enzyme heme oxygenase and therefore remain intact until they are excreted. Recently, SnPP was administered to a 2.5-month-old girl,1 and two 17-year-old boys were successfully treated with two cycles of prolonged SnMP therapy.2