TY - JOUR
T1 - Dual gene defects involving δ-aminolaevulinate dehydratase and coproporphyrinogen oxidase in a porphyria patient
AU - Akagi, Reiko
AU - Inoue, Rikako
AU - Muranaka, Shikibu
AU - Tahara, Tsuyoshi
AU - Taketani, Shigeru
AU - Anderson, Karl E.
AU - Phillips, John D.
AU - Sassa, Shigeru
PY - 2006/1
Y1 - 2006/1
N2 - A Caucasian male had symptoms of acute porphyria, with increases in urinary δ-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→q1C, 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.
AB - A Caucasian male had symptoms of acute porphyria, with increases in urinary δ-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→q1C, 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.
KW - Coproporphyrinogen oxidase
KW - Hepatic porphyria
KW - δ-aminolaevulinate dehydratase
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U2 - 10.1111/j.1365-2141.2005.05852.x
DO - 10.1111/j.1365-2141.2005.05852.x
M3 - Article
C2 - 16398658
AN - SCOPUS:33644816769
SN - 0007-1048
VL - 132
SP - 237
EP - 243
JO - British Journal of Haematology
JF - British Journal of Haematology
IS - 2
ER -