F Zolezzi

Publications (7)26.45 Total impact

• Article: Four new cases of lethal osteogenesis imperfecta due to glycine substitutions in COL1A1 and genes. Mutations in brief no. 152. Online.

  M Mottes, M Gomez Lira, F Zolezzi, M Valli, V Lisi, P Freising
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  ABSTRACT: Perinatal lethal osteogenesis imperfecta is the result of heterozygous mutations of the COL1A1 and COL1A2 genes. Here we describe the molecular defects responsible for four case of lethal OI. Two glycine substitutions within the COL1A1 gene (G478S, G994D) and two glycine substitutions within the COLIA2 gene (G319V, G697C) were identified. The mutation sites were localized in proalpha2(I) and proalpha2(I)mRNA molecules, respectively, by chemical cleavage of mismatch in hereteroduplex nucleic acids. Subsequent reverse transcription PCR amplification, cloning and sequencing, led to mutation identification. The aminoacid substitutions were due to two G-->A transitions in COL1A1(cases 1,2), to a G-->T transversion in COL1A2 (case 3), and to two contiguous point mutations in COL1A2 (case 4). All five nucleotide changes appeared to be fresh mutations. COLIA1(accession number Z74615) and COL1A2(accession number Z74616) wild type coding sequences (cDNA) were deduced from the EMBL DNA sequence database. The mutations described here can also be found in the human type I collagen mutation database at the web site:http://www.le.ac.uk/genetics/collagen.
  Human Mutation 02/1998; 12(1):71-2. · 5.69 Impact Factor
• Article: Mutation producing alternative splicing of exon 26 in the COL1A2 gene causes type IV osteogenesis imperfecta with intrafamilial clinical variability.

  F Zolezzi, M Valli, M Clementi, I Mammi, G Cetta, P F Pignatti, M Mottes
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  ABSTRACT: We have characterized a familial form of osteogenesis imperfecta (OI). Following the identification by ultrasound of short limbs and multiple fractures in a fetus at 25 weeks of gestation, the family was referred with a provisional diagnosis of severe OI. We detected subtle clinical and radiological signs of OI in the father and in the paternal grandmother of the proposita, who had never received a diagnosis of OI. Linkage analysis indicated COL1A2 as the disease locus. Heteroduplex analysis of reverse transcription-polymerase chain reaction (RT-PCR) amplification products of pro alpha2(I) mRNA from an affected member and subsequent sequencing of the candidate region demonstrated the presence of normal transcripts and a minority of transcripts lacking exon 26 (54 bp) of COL1A2. Sequencing of PCR-amplified genomic DNA identified an A --> G transition in the moderately conserved +3 position of the IVS 26 donor splice site. The mutant pre-mRNA molecules were alternatively spliced, yielding both full-length and deleted transcripts that represented less than 30% of the total pro alpha2(I) mRNA. The biochemical data on type I collagen synthesized by dermal fibroblasts showed intracellular retention of the mutant protein; failure to detect the shortened alpha2(I) chains either in the medium or in the cell layer may be the consequence of their instability at physiological temperature. These observations justified the mild resulting phenotype.
  American Journal of Medical Genetics 08/1997; 71(3):366-70.
• Article: Intrafamilial variable expressivity of osteogenesis imperfecta due to mosaicism for a lethal G382R substitution in the COL1A1 gene.

  L Cohen-Solal, F Zolezzi, P F Pignatti, M Mottes
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  ABSTRACT: Fibroblasts from a 23 week old fetus affected with lethal (type II) osteogenesis imperfecta (OI) produced normal and abnormal type I procollagen molecules. The abnormal molecules were shown to contain pro alpha 1(I) chains in which the glycine at position 382 of the triple helical domain was substituted by arginine, as the result of a G-to-C transversion at nucleotide 1797 of the pro alpha (I) coding sequence. Also fibroblasts from the apparently normal father produced abnormal type I collagen but the overmodified alpha 1(I) chains tended to disappear with increasing passage number. We determined that the mutant allele accounted for approximately 36% of the COL1A1 alleles in the father's skin fibroblasts. Upon careful clinical reexamination, the man appeared to be very mildly affected with OI. The most plausible explanation for such a phenotypic variation is that the father is a mosaic for a mutation that is lethal in the heterozygous son. This finding confirms previous observations that somatic mosaicism for new dominant mutations is responsible for extreme intrafamilial variability and poses some caveats in genetic counselling.
  Molecular and Cellular Probes 07/1996; 10(3):219-25. · 2.08 Impact Factor
• Article: A 931 + 2T-->C transition in one COL1A2 allele causes exon 16 skipping in PRO alpha 2(I) mRNA and produces moderately severe OI.

  F Zolezzi, A Forlino, M Mottes, M Valli, A Sensi, E Calzolari, P F Pignatti, G Cetta
  Human Mutation 02/1995; 6(3):268-71. · 5.69 Impact Factor
• Article: Severe (type III) osteogenesis imperfecta due to glycine substitutions in the central domain of the collagen triple helix.

  A Forlino, F Zolezzi, M Valli, P F Pignatti, G Cetta, P C Brunelli, M Mottes
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  ABSTRACT: The molecular defects responsible for three cases of severe (type III) osteogenesis imperfecta (OI) were investigated. The mutation sites were localized in pro alpha 1(I) and pro alpha 2(I) mRNA molecules, respectively, by chemical cleavage of mismatch in heteroduplex nucleic acids. Mutation identification was achieved by reverse transcription-polymerase chain reaction-DNA amplification, followed by cloning and sequencing. Two unrelated patients were demonstrated to bear the same G-A transition at nucleotide 2418 of the pro alpha 1(I) coding region, leading to G589S substitution and resulting in very similar clinical manifestations. In the latter patient, a G-T transversion at nucleotide 2166 was found in one pro alpha 2(I) allele, which caused a G586V substitution and again severe OI. Presumably all three mutations occurred de novo in the probands, since they were not found in their parents' DNA. The biochemical findings on type I collagen were very similar in all the probands: the mutations here described had little destabilizing effects on triple helix formation, secretion and stability. The half-life of the collagen incorporated into the insoluble matrix was comparable with that of controls. These mutations are localized in the gap zone of the fibrils where mineral nucleation occurs. This fact suggests that they probably do not exert destabilizing effects on the individual collagen molecules, but rather on the mineralization process, once the defective molecules are incorporated into the fibrils, hence causing severe phenotypes.
  Human Molecular Genetics 01/1995; 3(12):2201-6. · 7.64 Impact Factor
• Article: Gly85 to Val substitution in pro alpha 1(I) chain causes mild osteogenesis imperfecta and introduces a susceptibility to protease digestion.

  M Valli, F Zolezzi, M Mottes, F Antoniazzi, F Stanzial, R Tenni, P Pignatti, G Cetta
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  ABSTRACT: In this paper we describe a mild moderate form of osteogenesis imperfecta caused by a point mutation in COL1A1 which converted glycine 85 to valine. The valine substitution introduced into the triple-helical domain of type-I collagen a conformational perturbation causing susceptibility to digestive proteases. In fact, SDS/PAGE of pepsin-treated collagen showed the presence of a faint band, migrating between alpha 1(I) and alpha 2(I), both in the medium and in the cell layer. On trypsin digestion the band, a shortened form of alpha 1(I), had a melting temperature of 39.5 degrees C. If the triple-helical collagen was obtained after trypsin or chymotrypsin digestion of procollagen, two shortened bands were identified; the enzymes cleaved about 40% of the trimers. The mutant procollagen was normally secreted and processed in the extracellular matrix at a normal rate. When native type-I collagen was formed after dextran-sulfate incubation, only chains of normal length were found, suggesting that the fibroblast proteases did not recognize the alteration introduced by the mutation. The effects of glycine 85 to valine substitution are compared with those produced by a previously described arginine substitution of the same residue (Deak et al., 1991).
  European Journal of Biochemistry 11/1993; 217(1):77-82. · 3.58 Impact Factor
• Article: Allelic frequencies of FBN1 gene polymorphisms and genetic analysis of italian families with Marfan syndrome.

  M Mottes, S Mirandola, F Rigatelli, F Zolezzi, V Lisi, D Gordon, P F Pignatti
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  ABSTRACT: The fibrillin gene (FBN1) is the disease locus for Marfan syndrome. This disorder shows a high degree of clinical and allelic heterogeneity. Direct mutation screening has proven difficult and inefficient and at present cannot be utilized for routine analysis. In familial cases linkage analysis represents a useful tool for molecular diagnosis. We have determined the allelic frequencies of 5 polymorphic markers within the FBN1 locus in the Italian population and have successfully employed them for prenatal diagnosis and resolution of clinically equivocal cases.
  Human Heredity 50(3):175-9. · 1.79 Impact Factor