Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-11-20
pubmed:abstractText
Acute intermittent porphyria (AIP) is a low-penetrant, autosomal dominant disorder caused by mutations in the HMBS gene. The gene is transcribed from two promoters to produce ubiquitous and erythroid isoforms of porphobilinogen deaminase, which differ only at their NH2 ends. In the classical form of AIP, both isoforms are deficient, but about 5% of families have the non-erythroid variant in which only the ubiquitous isoform is affected. Previously identified mutations in this variant have been within or close to the coding region of exon 1 of the HMBS gene, the only exon that is expressed solely in the ubiquitous isoform. Here, we describe mutations in the ubiquitous promoter (-154delG) and in exon 3 (41delA) that cause the non-erythroid variant. Reporter gene and electrophoretic mobility shift assays show that the G nucleotide at position -154, the most 5' of several transcription-initiation sites in the ubiquitous HMBS promoter, which lies immediately 3' to a transcription-factor IIB binding motif, is essential for normal transcription. The frameshift mutation in exon 3 introduces a stop codon into mRNA for the ubiquitous isoform only. Our investigations identify two new mechanisms for production of the non-erythroid variant of AIP and demonstrate that mutational analysis for diagnosis of this variant needs to include wider regions of the HMBS gene than indicated by previous reports. Furthermore, they show that deletion of one of several transcription initiation sites in the promoter of a housekeeping gene that lacks both TATA and initiator elements can produce disease.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0340-6717
pubmed:author
pubmed:issnType
Print
pubmed:volume
107
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
243-8
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:11071386-Adolescent, pubmed-meshheading:11071386-Adult, pubmed-meshheading:11071386-Base Sequence, pubmed-meshheading:11071386-Binding Sites, pubmed-meshheading:11071386-Child, Preschool, pubmed-meshheading:11071386-Exons, pubmed-meshheading:11071386-Female, pubmed-meshheading:11071386-Frameshift Mutation, pubmed-meshheading:11071386-Humans, pubmed-meshheading:11071386-Hydroxymethylbilane Synthase, pubmed-meshheading:11071386-Male, pubmed-meshheading:11071386-Molecular Sequence Data, pubmed-meshheading:11071386-Porphyria, Acute Intermittent, pubmed-meshheading:11071386-Porphyria, Erythropoietic, pubmed-meshheading:11071386-Promoter Regions, Genetic, pubmed-meshheading:11071386-Protein Isoforms, pubmed-meshheading:11071386-Transcription Factor TFIIB, pubmed-meshheading:11071386-Transcription Factors
pubmed:year
2000
pubmed:articleTitle
Non-erythroid form of acute intermittent porphyria caused by promoter and frameshift mutations distant from the coding sequence of exon 1 of the HMBS gene.
pubmed:affiliation
Department of Medical Biochemistry, University Hospital of Wales and Llandough Hospital NHS Trust and University of Wales College of Medicine, Cardiff, UK.
pubmed:publicationType
Journal Article