Congenital erythropoietic porphyria due to a mutation in GATA1: the first trans-acting mutation causative for a human porphyria.
Congenital erythropoietic porphyria (CEP), an autosomal recessive disorder, is due to mutations of uroporphyrinogen III synthase (UROS). Deficiency of UROS results in excess uroporphyrin I, which causes photosensitization. We evaluated a 3-year-old boy with CEP. A hypochromic, microcytic anemia was present from birth, and platelet counts averaged 70 x 10(9)/L (70,000/microL). Erythrocyte UROS activity was 21% of controls. Red cell morphology and globin chain labeling studies were compatible with beta-thalassemia. Hb electrophoresis revealed 36.3% A, 2.4% A(2), 59.5% F, and 1.8% of an unidentified peak. No UROS or alpha- and beta-globin mutations were found in the child or the parents. The molecular basis of the phenotype proved to be a mutation of GATA1, an X-linked transcription factor common to globin genes and heme biosynthetic enzymes in erythrocytes. A mutation at codon 216 in the child and on one allele of his mother changed arginine to tryptophan (R216W). This is the first report of a human porphyria due to a mutation in a trans-acting factor and the first association of CEP with thalassemia and thrombocytopenia. The Hb F level of 59.5% suggests a role for GATA-1 in globin switching. A bone marrow allograft corrected both the porphyria and the thalassemia.
Phillips
John D
JD
Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA. john.phillips@hsc.utah.edu
Steensma
David P
DP
Pulsipher
Michael A
MA
Spangrude
Gerald J
GJ
Kushner
James P
JP
D000595:Amino Acid Sequence; D002675:Child, Preschool; D005260:Female; D050982:GATA1 Transcription Factor / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D017092:Porphyria, Erythropoietic / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D011485:Protein Binding; D015533:Transcriptional Activation / Q000235:genetics*; D016335:Zinc Fingers
D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human