RESUMO
We report the case of a young male presenting with cholestatic liver failure. After an extensive workup, the etiology of the liver failure was determined to be due to hereditary coprophorphyria (HCP). The inciting event was the use of Hydroxycut™, an over-the-counter supplement to promote weight loss that has been reported to cause oxidative liver injury in vulnerable populations. Although HCP is a rare cause of cholestatic liver failure, it is treatable if diagnosed correctly and in a timely manner. In this clinical vignette, we discuss a case that highlights the genetic susceptibility to disease that can be unmasked by environmental exposures. We also review the relevant literature on Hydroxycut™ and how it can affect hepatic function.
Assuntos
Coproporfiria Hereditária/complicações , Coproporfiria Hereditária/diagnóstico , Falência Hepática/etiologia , Preparações de Plantas/administração & dosagem , Coproporfiria Hereditária/genética , Coproporfirinogênio Oxidase/genética , Mutação da Fase de Leitura , Humanos , Masculino , Porfirinas/sangue , Adulto JovemRESUMO
Summary A Caucasian male had symptoms of acute porphyria, with increases in urinary delta-aminolaevulinic acid (ALA), porphobilinogen (PBG) and coproporphyrin that were consistent with hereditary coproporphyria (HCP). However, a greater than expected increase in ALA, compared with PBG, and a substantial increase in erythrocyte zinc protoporphyrin, suggested additional ALA dehydratase (ALAD) deficiency. Nucleotide sequence analysis of coproporphyrinogen oxidase (CPO) cDNA of the patient, but not of the parents, revealed a novel nucleotide transition G835-->C, resulting in an amino acid change, G279R. The mutant CPO protein expressed in Escherichia coli was unstable, and produced about 5% of activity compared with the wild-type CPO. Erythrocyte ALAD activity was 32% of normal in the proband. Nucleotide sequence analysis of cloned ALAD cDNAs from the patient revealed a C36-->G base transition (F12L amino acid change). The F12L ALAD mutation, which was found in the mother and a brother, was previously described, and is known to lack any enzyme activity. This patient thus represents the first case of porphyria where both CPO and ALAD deficiencies were demonstrated at the molecular level.