Dana Ulbrichova, Matous Hrdinka, Eva Flachsová, Ivan Mikula, Michaela Bodnarova, Jana Prochazkova, Jana Saligova1, Eva Silhanova2, Hana Halamkova3, Jiri Zeman, Pavel Martasek
Department of Pediatrics, Ist School of Medicine, Charles University, 128 08 Prague, Czech Republic; 1Department of Pediatrics, University Hospital Kosice, Slovak Republic; 2Department of Clinical Genetics, University Hospital Ostrava, Czech Republic; 3Department of Biochemistry, Regional Hospital Vyskov, Czech Republic
BACKGROUND: Acute intermittent porphyria (AIP; OMIM 176000) is an autosomal dominant disorder caused by the partial deficiency of porphobilinogen deaminase (PBGD; or hydroxymethylbilane synthase, HMBS; EC 4.3.1.8), the third enzyme in the heme biosynthetic pathway. It is manifested by life-threatening acute neurological attacks that can be provoked by various factors, including certain drugs, hormones, alcohol and starvation. Clinical expression is highly variable, and ~90% of AIP heterozygotes remain asymptomatic throughout life. To date, over 250 HMBS mutations have been identified.
OBJECTIVE: To identify the molecular lesions in newly diagnosed (2004) Czech and Slovak AIP patients.
DESIGN AND METHODS: Genomic DNA was isolated from members of seven unrelated AIP families from the Czech and Slovak Republics, and mutation screening was performed by PCR and denaturing gradient gel electrophoresis (DGGE). Subsequently, automated DNA sequencing was used to verify the mutated lesions. For each identified mutations, a restriction fragment length polymorphism (RFLP) assay was established, and a total of 36 individuals from seven families were analyzed to detect asymptomatic carriers.
RESULTS: Eight mutations were identified, including three novel mutations (610 C>A, 675 delA, 966 insA), and five previously reported mutations (76 C>T, 77 G>A, 518 G>A, 771+1 G>T, 973 insG). This is the first report of the 518 G>A mutation in the Czech and Slovak population. Of particular interest, one patient had two mutations, 518 G>A and 610 C>A, both located in exon 10.
CONCLUSIONS: Three novel mutations were identified in seven unrelated AIP families. These studies further emphasize the molecular heterogeneity of AIP, and provide accurate detection of asymptomatic carriers.
(Supported by grant GAUK 10/2004/C)