Human protoporphyria: genetic heterogeneity at the ferrochelatase locus.

Inherited deficiency of ferrochelatase results in erythropoietic protoporphyria (EPP). Genetic heterogeneity at the locus for human ferrochelatase was investigated. Analysis of genomic DNA of patients with EPP and of control subjects by restriction endonuclease techniques using ten different enzymes detected polymorphisms only at sites recognized by EcoRI, HincII, PstI and TaqI.

Distribution of ferrochelatase activity in density gradient separated bone marrow cells.

A simple, reproducible, and economical procedure for separating bone marrow cells into distinct populations and stages of maturation was developed and used to investigate the distribution of ferrochelatase activity in rat bone marrow cells. Density gradient ultracentrifugation of normal rat marrows on discontinuous arabinogalactan layers of 16.5-30.

A novel mutation in erythropoietic protoporphyria: an aberrant ferrochelatase mRNA caused by exon skipping during RNA splicing.

An aberrant ferrochelatase mRNA lacking exon 10 was found in a patient with erythropoietic protoporphyria (EPP). In her genomic DNA an A-->T transversion at position -3 of the donor site of intron 10 appeared to be responsible for the exon skipping. Both the patient and her sister were heterozygous for this mutation.

Molecular cloning of a cDNA for human delta-aminolevulinate dehydratase.

A cDNA encoding human delta-aminolevulinic acid dehydratase (ALA-D; EC 4.2.1.

Acute intermittent porphyria: characterization of a novel mutation in the structural gene for porphobilinogen deaminase. Demonstration of noncatalytic enzyme intermediates stabilized by bound substrate.

To investigate the molecular pathology in acute intermittent porphyria (AIP), the nature of the defective porphobilinogen (PBG)-deaminase was determined in erythrocyte lysates from 165 AIP heterozygotes from 92 unrelated families representing 20 different ethnic or demographic groups. Immunologic and physicokinetic studies revealed the occurrence of four classes of PBG-deaminase mutations. In the majority of families studied, the amount of immunoreactive enzyme protein corresponded to the amount of enzymatic activity, indicating the absence of cross-reacting immunologic material (CRIM) produced by the mutant allele.