engleski

Croatian population: are there any mutations and polymorphisms in PMM2 and ALG6 genes

CROATIAN POPULATION: ARE THERE ANY MUTATIONS AND POLYMORPHISMS IN PMM2 AND ALG6 GENE S. Supraha, G. Lauc and J. Dumic Department of Biochemistry and Molecular Biology, Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovacica 1, Zagreb, Croatia E-mail: sandras@pharma.hr The most common types of congenital disorders of glycosylation (CDGs) are CDG Ia and CDG Ic. Type Ia is caused by reduced N-glycosylation due to phosphomannomutase 2 deficiency as a consequence of mutations in PMM2 gene. The most frequent single-base mutations are present in exon 5, 422G>A and 357C>A, resulting in R141H and F119L substitution, respectively. CDG Ic is caused by mutations in ALG6 gene, encoding Man(9)GlcNAc(2)-PP-Dol α 1, 3-glucosyltransferase. The most significant mutation found in this gene C998T resulting in an A333V substitution has so far been detected in patients of European origin. We have recently undertaken a comprehensive project to determine the frequency of various mutations/polymorphisms in PMM2 and ALG6 genes in Croatian population. Until now no patient with CDG was detected in Croatia. Here we present results of screening for mutations in the exon 5 and parts of intervening sequences IVS4 and IVS5 of PMM2 gene and exon 11 of ALG6 gene. Up today we analyzed samples obtained of 350 unrelated Croats. Screening for R141H and F119L was performed using PCR-SSCP analysis (6% PAG-electrophoresis, 15 C, 5 hrs, 3W). 24 fragments that showed aberrant electrophoretic patterns were additionally sequenced on ABIPrism 310 Genetic Analyzer. R141H and F119L mutations were not found in the analyzed group. However, we detected six homozygotes for IVS5+19T/T, three homozygotes for IVS5+19C/C and fifteen heterozygotes (IVS5+19T/C) for intragenic single nucleotide polymorphism IVS5+19T/C, while all 24 individuals were homozygous for IVS5+22T/T. One of the heterozygotes for IVS5+19T/C was also a heterozygote for deletion of 3bp (ATG) on the position -58 in intron 4. To be able to analyze the frequency of A333V mutation in ALG6 gene we optimized PCR-SSCP procedure: electrophoresis was performed on 6% PAG, at 4 C for 5 hours using 6W. In the samples analyzed until now A333V mutation has not been identified. were additionally sequenced on ABIPrism 310 Genetic Analyzer. R141H and F119L mutations were not found in the analyzed group. However, we detected six homozygotes for IVS5+19T/T, three homozygotes for IVS5+19C/C and fifteen heterozygotes (IVS5+19T/C) for intragenic single nucleotide polymorphism IVS5+19T/C, while all 24 individuals were homozygous for IVS5+22T/T. One of the heterozygotes for IVS5+19T/C was also a heterozygote for deletion of 3bp (ATG) on the position -58 in intron 4. To be able to analyze the frequency of A333V mutation in ALG6 gene we optimized PCRSSCP procedure: electrophoresis was performed on 6% PAG, at 4 C for 5 hours using 6W. In the samples analyzed until now A333V mutation has not been identified.

mutations; PMM2; ALG6; polymorphism

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