Biomedical subjects

Maurizio Travi

Publications and source records attributed to Maurizio Travi.

5 recordsLinked to original sources

PubMed2006

Thalassaemia-like carriers not linked to the beta-globin gene cluster.

This study describes the largest series reported to date, of individuals belonging to unrelated families carrying a beta-thalassaemia-like phenotype in whom the beta-globin gene was found to be structurally intact by sequence analysis. This genetic determinant appears haematologically heterogeneous, displaying either a silent beta-thalassaemia-like phenotype or a typical beta-thalassaemia carrier-like phenotype in different families. Compound heterozygosity for both beta-thalassaemia-like determinant and typical beta-thalassaemia allele resulted either in thalassaemia intermedia or thalassaemia major. By linkage analysis both the silent and the typical beta-like determinants were found not to be linked to the beta-globin cluster. Sequence analysis of the hypersensitive site cores of locus control region and of the genes coding for the transcription factors erythroid Kruppel-like factor and nuclear factor (erythroid-derived 2) were normal. beta-globin mRNA levels determined by real-time polymerase chain reaction were reduced in both types of beta-like carriers. These results indicate the existence of causative genetic determinants not yet molecularly defined, but most likely, resulting from either the reduction or loss of function of a gene coding for unknown transcriptional regulator(s) of the beta-globin gene. The knowledge of these rare beta-thalassaemia-like determinants have implications for clinical and, especially, prenatal diagnosis of beta-thalassaemia.

Alleles↗

PubMed2006

Different approaches for noninvasive prenatal diagnosis of genetic diseases based on PNA-mediated enriched PCR.

The aim of this work was to develop advanced and accessible protocols for noninvasive prenatal diagnosis of genetic diseases. We are evaluating different technologies for mutation detection, based on fluorescent probe hybridization of the amplified product and pyrosequencing, a technique that relies on the incorporation of nucleotides in a primer-directed polymerase extension reaction. In a previous investigation, we have already proven that these approaches are sufficiently sensitive to detect a few copies of a minority-mutated allele in the presence of an excess of wild-type DNA, In this work, in order to further enhance the sensitivity, we have employed a mutant enrichment amplification strategy based on the use of peptide nucleic acids (PNAs). These DNA analogues bind wild-type DNA, thus interfering with its amplification while still allowing the mutant DNA to become detectable. We have synthesized different PNAs, which are highly effective in clamping wild-type DNA in the beta-globin gene region, where four beta-thalassemia mutations are located (IVSI.110, CD39, IVSI.1, IVSI.6) plus HbS. The fluorescence microchip readout allows us to monitor the extent of wild-type allele inhibition, thus facilitating the assessment of the optimal PNA concentration.

DNA↗

PubMed2005

Detection of a novel dystrophin gene mutation through carrier analysis performed during prenatal diagnosis in a case with intragenic recombination.

OBJECTIVES: To report a multi-technical approach to Duchenne muscular dystrophy (DMD) mutation testing through carrier analysis, in the prenatal diagnosis of a male foetus without a known mutation segregating in the family and with inconclusive results of linkage analysis. METHODS: Haplotype analysis with the DMD region markers for assigning the carrier status of the mother and for prenatal diagnosis of foetal DNA; semiquantitative multiplex analysis of maternal and foetal DNA for the promoter and for 34 exons of the DMD gene; sequencing analysis of the maternal and foetal DNA for confirmation of the results. RESULTS: Because of an intragenic recombination of the DMD gene in foetal DNA, haplotype analysis gave inconclusive results. Semiquantitative PCR analysis displayed a pattern compatible with a heterozygous exon 60 mutation in the mother's DNA, while foetal DNA showed a normal migration pattern. Sequencing analysis confirmed the presence of a novel 7 base-pair deletion in exon 60 of the DMD gene in the mother and excluded the deletion in the foetus. CONCLUSION: Semiquantitative PCR results allowed the DMD mutation detection in the mother and the exclusion in the foetus, showing its crucial importance in prenatal diagnosis in those cases where linkage analysis is not conclusive.

DNA Mutational Analysis↗

PubMed2005

Simultaneous mutations in the CLCNKB and SLC12A3 genes in two siblings with phenotypic heterogeneity in classic Bartter syndrome.

Two siblings (brother and sister) with renal tubular hypokalemic alkalosis underwent clinical, biochemical and molecular investigations. Although the biochemical findings were similar (including hypokalemia, metabolic alkalosis, hyperreninemia, hyperaldosteronism and normal blood pressure), the clinical findings were different: the boy, who also presented syndromic signs, developed glomerular proteinuria and renal biopsy revealed focal segmental glomerular sclerosis; the girl showed the typical signs of classic Bartter syndrome. As described in a previous paper, a heterozygous mutation (frameshift 2534delT) was demonstrated in the gene encoding the thiazide-sensitive NaCl co-transporter (SLC12A3) of the distal convoluted tubule; the second molecular analysis revealed a compound heterozygous mutation (A61D/V149E) in the CLCNKB chloride channel gene in both subjects, inherited in trans from the parents. The children were finally diagnosed as having classic Bartter syndrome. These cases represent the first report of the simultaneous presence of heterozygous and compound heterozygous mutations in the SLC12A3 and CLCNKB genes, both of which are involved in renal salt losing tubulopathies, and confirm previous observations regarding classic Bartter syndrome phenotype variability in the same kindred.

Adult↗

PubMed2004

Beta-thalassemia microelectronic chip: a fast and accurate method for mutation detection.

BACKGROUND: beta-Thalassemia is one of the most common genetic diseases in humans. We developed an automated electronic microchip for fast and reliable detection of the nine most frequent mutations accounting for >95% of the beta-thalassemia alleles in the Mediterranean area. METHODS: We developed a microchip-based assay to identify the nine most frequent mutations (cd39C>T, IVS1-110G>A, IVS1-1G>A, IVS1-6T>C, IVS2-745C>G, cd6delA, -87C>G, IVS2-1G>A, and cd8delAA) by use of the Nanogen Workstation. The biotinylated amplicon was electronically addressed on the chip to selected pads, where it remained embedded through interaction with streptavidin in the permeation layer. The DNA at each test site was then hybridized to a mixture of fluorescently labeled wild-type or mutant probes. RESULTS: Assays conditions were established based on the analysis of 700 DNA samples from compound heterozygotes or homozygotes for the nine mutations. The assays were blindly validated on 250 DNA samples previously genotyped by other methods, with complete concordance of results. Alternative multiplexed formats were explored: the combination of multiplex PCR with multiple addressing and/or hybridization allowed analysis of all nine mutations in the same sample on one test site of the chip. CONCLUSIONS: The open flexible platform can be designed by the user according to the local prevalence of mutations in each geographic area and can be rapidly extended to include the remaining mutations causing beta-thalassemia in other regions of the world.

Fluorometry↗