++ HMBS Sanger Sequencing for Acute Intermittent Porphyria
Acute Intermittent Porphyria (AIP) is the commonest form of the acute hepatic porphyrias and is caused by pathogenic variants in the HMBS gene.
All 15 exons and the promoter region of the HMBS gene are amplified in 12 amplicons. 5’ and 3’ primers specific for each amplicon are used to amplify the regions. Each of the primers carries an M13 F or R tag to ensure the entire product can be sequenced.
++ PPOX Sanger Sequencing for Variegate Porphyria
Variegate Porphyria (VP) is one of the acute porphyrias and is caused by pathogenic variants in the PPOX gene. VP is about one-third as prevalent as Acute Intermittent Porphyria (AIP) in most European countries but is more common in South Africa.
All 13 exons and the promoter region of the PPOX gene are amplified in 13 amplicons. 5’ and 3’ primers specific for each amplicon are used to amplify the regions. Each of the primers carries an M13 F or R tag to ensure the entire product can be sequenced.
++ Variegate Porphyria PPOX Gene R59W Detection
In South Africa the incidence of variegate porphyria (VP) is approx. 3 in 1000 with the c.175C>T; p.Arg59Trp variant in the PPOX gene being responsible for the vast majority of these cases. In the UK the incidence is much lower, however this is still the most commonly searched for variant in a patient presenting with possible variegate porphyria.
The relevant region of the PPOX genomic sequence is PCR-amplified. Mutant and wild type sequences are differentiated by specific fluorescently labelled probes. TaqMan PCR is used for this purpose.
++ Red Cell Gene Panel: Porphyria Subpanel.
Comprehensive sequencing service for all the known genes associated with porphyria is available in a single next-generation sequencing panel. Full gene coverage including all exons +/- 50bp intron/exon boundaries.
Genes: ALAD , ALAS2 , CPOX , FECH , GATA1 , HMBS , PPOX , UROD , UROS
For more information, please visit the Red Cell Gene Panel (RCGP) test page.
Clotted samples are unsuitable for DNA analysis.
Blood Samples in in correct anticoagulant tubes may be rejected.
We accept DNA samples. Please provide at least 1-5µg of purified DNA
For prenatal diagnosis please refer to section for sample requirements.
Blood Sciences Laboratory
Ground Floor Bessemer Wing
King’s College Hospital
London SE5 9RS
Last updated: 15/01/2020