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Mirella Filocamo

Publications and source records attributed to Mirella Filocamo.

30 records · Page 2Linked to original sources
PubMed2004

Wolman disease and cholesteryl ester storage disease diagnosed by histological and ultrastructural examination of intestinal and liver biopsy.

Deficient activity of lysosomal acid lipase (LAL) results in massive accumulation of cholesteryl esters and triglycerides in most tissues of the body. The deficiency state is expressed in two major phenotypes: Wolman disease (WD) and cholesteryl ester storage disease (CESD). WD occurs in infancy and is nearly always fatal before the age of 1 year, whereas CESD can be more benign and may not be detected until adulthood. Since there are no specific routine laboratory observations that suggest these metabolic diseases, diagnosis is based on the clinical picture combined with LAL deficiency in cultured skin fibroblasts or peripheral lymphocytes. Both disorders are rather rare, considering that about a hundred of cases have been described up to now. This study describes the histological and ultrastructural aspects disclosed by intestinal or liver biopsy in three cases of WD and in two cases of CESD. Furthermore, it emphasizes the role of morphological findings in pointing the diagnosis towards a metabolic storage disease.

Biopsy↗
PubMed2004

An unusual arylsulfatase A pseudodeficiency allele carrying a splice site mutation in a metachromatic leukodystrophy patient.

A late infantile metachromatic leukodystrophy patient was found to be heterozygous for the arylsulfatase A (ARSA) pseudodeficiency (pd) polyadenylation site variant ((*)96A>G) in the absence of the commonly associated N-glycosylation site variant (N350S). ARSA alleles were sequenced and the genotype completely defined. Six sequence variations were identified, among which two resulted as severe disease-causing mutations, both leading to the loss of the reading frame: a splice acceptor site mutation in intron 4 (849-1G>A), located on the (*)96A>G allele and a mononucleotide deletion (258delC) in exon 2, located on the other allele. The altered splicing caused by the 849-1G>A mutation was shown by in vitro expression of a recombinant gene containing the genomic region surrounding the mutation. Haplotype analysis of the unusual pd allele was performed in order to investigate its possible origin.

Alleles↗
PubMed2004

Early visual seizures and progressive myoclonus epilepsy in neuronopathic Gaucher disease due to a rare compound heterozygosity (N188S/S107L).

PURPOSE: Gaucher disease, the inherited deficiency of the lysosomal enzyme glucocerebrosidase, is characterized by genotypic and phenotypic heterogeneity. We recently characterized the glucocerebrosidase alleles of a patient with an unusual clinical presentation of type 3 Gaucher disease. METHODS: Initial clinical manifestations appeared at age 11 years as visual seizures. RESULTS: Subsequent progressive myoclonus and generalized seizures were consistent with an adolescent-onset form of progressive myoclonus epilepsy. However, a specific diagnosis was established only at age 16, because of the absence of hematologic abnormalities and a fairly moderate hepatomegaly. Bone marrow aspirate was slightly positive for Gaucher cells. Demonstration of reduced glucocerebrosidase in the fibroblasts confirmed the diagnosis. The child died at age 19 years. Postmortem sequencing of the glucocerebrosidase gene from cultured fibroblasts demonstrated a rare compound heterozygote for N188S/S107L. CONCLUSIONS: This unusual presentation of Gaucher disease indicates that if clinical and neurophysiological findings in adolescents with initial visual seizures and myoclonus suggest a progressive disorder, enzymatic assay is mandatory, even in the absence of the classic neurologic and systemic signs of the disease. Early differential diagnosis from other forms of progressive myoclonus epilepsy with similar clinical presentation may help provide appropriate genetic counseling.

Child↗
PubMed2003

Expression studies of two novel in CIS-mutations identified in an intermediate case of Hunter syndrome.

Hunter syndrome (Mucopolysaccharidosis type II) is a rare X-linked recessive lysosomal storage disorder caused by the deficiency of the enzyme iduronate-2-sulfatase (IDS). To date, more than 200 different mutations have been reported in the IDS gene, located on Xq27.3-q28. Here, we report two new mutations (M488I and G489A) identified in hemizygosity in an Italian Hunter patient. Their "in vitro" expression by COS 7 cells was carried out in order to evaluate their functional consequence on enzyme activity as well as their possible cumulative effect on the malfunctioning of the protein. The results obtained enabled us to confirm the G489A mutation as causative. The M488I mutation, however, could not be unequivocally considered as causing disease because of its residual activity. Although a cumulative effect of the two mutations can be excluded "in vitro," we are cautious about drawing a conclusion with regard to the possible role that the two mutations could have played "in vivo" in modulating the phenotype of the patient. Finally, the knowledge of the molecular defect of the patient has enabled us to identify the carriers, providing reliable genetic counselling to the females of the family.

Animals↗
PubMed2003

An Alu-mediated rearrangement as cause of exon skipping in Hunter disease.

Hunter syndrome (Mucopolysaccharidosis type II), a rare X-linked lysosomal storage disorder, results from deleterious mutations in the iduronate-2-sulfatase ( IDS) gene located on Xq27.3-q28. Partial or complete deletions and large rearrangements have been extensively reported in the IDS gene as the basis of Hunter disease. The present report, however, is the first report on a Hunter patient in which Alu-mediated recombinations are implicated. Our patient showed the skipping of exon 8 at the cDNA level, without any splice-junction defects at the genomic level, where a new large rearrangement was identified instead. This new mutant allele consisted of an extensive deletion of IDS sequence of about 3 kb, as well as an additional inserted sequence of 157 bp. Two different computer programs were necessary to elucidate the nature of the insert. NCBI-BLAST query detected a single match for 126 bp out of 157 of the fragment that aligned exactly with a specific chromosomal region, Xq25-27.1, where an AluSg sequence is adjacent to an L1. Instead, the Repeat Masker program identified only 83 bp out of 157 of the insert, which was confirmed as an AluS. The observed homology between the AluSc sequence in the IDS intron 8 and the inserted AluS element, as well as the closeness of 26 bp Alu core sequence, considered to be a recombination hotspot, made us hypothesise upon the fact that both an Alu retrotransposition and an Alu-mediated deletion underlie the disease-producing rearrangement. We, therefore, now propose a mechanism that led to the large genomic deletion causing the production of the aberrant mRNA splicing.

Alternative Splicing↗
PubMed2003

Basic fibroblast growth factor activates endothelial nitric-oxide synthase in CHO-K1 cells via the activation of ceramide synthesis.

In this study, we analyzed the intracellular mechanisms leading to basic fibroblast growth factor (bFGF)-dependent production of NO in Chinese hamster ovary (CHO)-K1 cells and a possible physiological role for such an effect. bFGF induces NO production through the activation of the endothelial form of NO synthase (eNOS), causing a subsequent increase in the cGMP levels. In these cells, the activation of eNOS by bFGF is Ca(2+)- and mitogen-activated protein kinase-independent. The translocation of the enzyme from the plasma membrane, where it is located in caveolae bound to caveolin 1, to the cytosol is the crucial step for the synthesis of NO through the eNOS isoform. We demonstrate that bFGF activates a sphingomyelinase to synthesize ceramide, which, in turn, allows the dissociation of eNOS from caveolin 1 and its translocation to the cytosol in the active form, where it catalyzes the synthesis of NO. In fact, drugs interfering with sphingomyelinase activity blocked bFGF activation of eNOS, and an increase in ceramide content was detected after bFGF treatment. Moreover, in fibroblasts derived from patients with Niemann-Pick disease, in which the enzyme is genetically inactive, bFGF is unable to elicit eNOS activation. The NO produced after bFGF treatment, through the activation of guanylyl cyclase and protein kinase G, mediates a mitogen-activated protein kinase-independent cell proliferation. In conclusion, our data show that, in CHO-K1 cells, bFGF regulates the activity of eNOS through a novel intracellular pathway, involving the induction of ceramide synthesis and that the NO released participates in bFGF proliferative activity.

Animals↗
PubMed2003

Severity of bone marrow involvement in patients with Gaucher's disease evaluated by scintigraphy with 99mTc-sestamibi.

UNLABELLED: Gaucher's disease is a lysosomal storage disorder due to a genetically transmitted deficiency of the enzyme glucocerebrosidase. In the most common form of the disease (type 1), accumulation of glucosylceramide in the reticuloendothelial cells of liver, spleen, and bone marrow leads to visceromegaly, anemia, thrombocytopenia, and osteopenia. Skeletal manifestations secondary to infiltration of the bone marrow by Gaucher's cells are detectable by radiography only in advanced stages. Imaging of bone marrow involvement can be performed indirectly by magnetic resonance techniques or by bone marrow scintigraphy with radiocolloids. However, both procedures lack specificity because the normal bone marrow, rather than the pathologic process, is imaged. The aim of this study was to assess the reliability of (99m)Tc-sestamibi scintigraphy for direct evaluation of bone marrow involvement. METHODS: Seventy-two patients with type 1 and 2 patients with type 3 Gaucher's disease (35 males, 39 females) were enrolled in the study. The mean age +/- SD was 31.9 +/- 16.5 y (range, 3-76 y), and the average duration of the disease manifestations when performing scintigraphy was 12.95 y (median, 10.5 y; range, 0-44 y). Forty-three of 74 patients had never received enzyme replacement therapy (ERT), whereas 31 patients were already being treated with ERT. (99m)Tc-Sestamibi was injected intravenously (6-8 MBq/kg of body weight) and imaging was recorded at the lower limbs 30 min after injection, at the plateau of tracer accumulation in the involved bone marrow. The scans were evaluated visually, assigning a semiquantitative score based on the extension and intensity of uptake in the bone marrow of the lower limbs (0 = no uptake; 8 = maximum uptake). The scintigraphic score was entered into complex statistical analysis, which included a series of clinical and blood chemistry parameters defining overall severity of the disease. RESULTS: (99m)Tc-Sestamibi scintigraphy showed that 71 of 74 patients had some degree of bone marrow involvement. The scintigraphic score was highly correlated with an overall clinical severity score index (SSI) and with various parameters contributing to the SSI, either positively or negatively. The highest correlation of the scintigraphic score was found with an overall biochemical marker of disease severity (serum chitotriosidase). ERT-naive patients showed high correlation of the scintigraphic score with the clinical SSI, with a radiographically based score, and with serum chitotriosidase. In the ERT-treated patients, the scintigraphic score was correlated with the clinical SSI, with hepatomegaly, and with hemoglobin. CONCLUSION: (99m)Tc-Sestamibi uptake reliably identifies bone marrow infiltration by Gaucher's cells. The scintigraphic score is helpful for defining the severity of bone marrow involvement and for comparing patients. (99m)Tc-Sestamibi scintigraphy, which provides topographic information about the sites involved by the disease, is highly correlated with other parameters of disease severity and appears to correlate with response to ERT.

Adolescent↗
PubMed2002

Contribution of arylsulfatase A mutations located on the same allele to enzyme activity reduction and metachromatic leukodystrophy severity.

The occurrence of different mutations on the same arylsulfatase A allele is not uncommon, due to the high frequency of several variants, among which the pseudodeficiency mutations are particularly important. We identified a late infantile metachromatic leukodystrophy patient carrying on one allele the new E253K mutation and the known T391S polymorphism, and on the other allele the common P426L mutation, usually associated with the adult or juvenile form of the disease, and the N350S and *96A>G pseudodeficiency mutations. To analyze the contribution of mutations located on the same allele to enzyme activity reduction, as well as the possible phenotype implications, we performed transient expression experiments using arylsulfatase A cDNAs carrying the identified mutations separately and in combination. Our results indicate that mutants containing multiple mutations cause a greater reduction of ARSA activity than do the corresponding single mutants, the total deficiency likely corresponding to the sum of the reductions attributed to each mutation. Consequently, each mutation may contribute to ARSA activity reduction, and, therefore, to the degree of disease severity. This is particularly important for the alleles containing a disease-causing mutation and the pseudodeficiency mutations: in these alleles pseudodeficiency could play a role in affecting the clinical phenotype.

Alleles↗
PubMed2002

Analysis of the glucocerebrosidase gene and mutation profile in 144 Italian gaucher patients.

Gaucher disease (GD), the most prevalent lysosomal storage disease characterized by a remarkable degree of clinical variability, results from deleterious mutations in the glucocerebrosidase gene (GBA). In this paper we report the molecular characterization of 144 unrelated Italian GD patients with the three types of the disease. The allelic frequencies of Italians are reported and the mutation profile is analyzed. Besides the common N370S, L444P, RecNciI, G202R, IVS2+1G>A, D409H, F213I mutations, the different molecular strategies, used for the mutation detection, identified the rare N107L, R131C, R170C, R170P, N188S, S196P, R285C, R285H, W312C, D399N, A446P, IVS10-1G>A, RecDelta55, total gene deletion, as well as 12 mutant alleles that were exclusively present in the Italian population until now: the previously reported R353G, N370S+S488P mosaicism, IVS8(-11delC)-14T>A), Rec I, Y418C, and the seven novel alleles D127X, P159T, V214X, T231R, L354X, H451R, and G202R+M361I. The wide phenotypic differences observed within the genotypic groups as well as between siblings implicate a significant contribution of other modifying genetic and/or non-genetic factors and claim a comprehensive valuation of the patient including clinical., biochemical and molecular investigations for prognosis, appropriate interventive therapy and reliable genetic counseling.

DNA↗
PubMed2002

Genomic structure of the human UDP-GlcNAc:dolichol-P GlcNAc-1-P transferase gene.

The UDP-GlcNAc:dolichol-P GlcNAc-1-P transferase catalyzes the first and committed step in the dolichol cycle, thus playing a fundamental role in the pathway for protein N-glycosylation. The structure of the GlcNAc-1-P transferase gene has been previously elucidated in mouse and hamster. Moreover, the human cDNA has been cloned. Using sequence database tools, we deduced the genomic structure of the human GlcNAc-1-P transferase gene, which was experimentally confirmed by sequence analysis. The gene is composed of 9 exons and spans 5.5 kb. All splice acceptor and donor sites conform to the canonical AG/GT rule. The 5'-end of the gene is different from previously reported, as, consequently, the N-terminal of the encoded protein, which is predicted to be 408 amino acids long. The transcription start site, determined by 5' RACE, occurs 180 nucleotides upstream of the translation initiation codon. Several potential transcription regulatory motifs, such as Sp-1, E4TF1 and ATF binding sites, were identified in the 5'-flanking region. A polyadenylation signal is located 466 bp downstream of the stop codon. The genomic organization of the gene is similar to that of the corresponding mouse and hamster genes, though extensive homology is restricted to the coding regions. Analysis of a panel of radiation hybrids led to the assignment of the GlcNAc-1-P transferase gene to chromosome 11, at 4.19 cR from NIB361, according to the location of the homologous sequences in the database at 11q23.

3' Untranslated Regions↗
PubMed2002

Nitric oxide production stimulated by the basic fibroblast growth factor requires the synthesis of ceramide.

Nitric oxide (NO) is an intracellular and intercellular mediator involved in the modulation of many physiologic and pathologic processes including the regulation of neoangiogenesis. We analyzed the effects of basic fibroblast growth factor (bFGF) on NO production in CHO-K1 cells and the intracellular mechanisms involved. bFGF induces NO production through activation of the endothelial NO synthase (eNOS), causing a subsequent increase in cGMP levels. In most systems, eNOS activation is a Ca(2+)-calmodulin-dependent process. In CHO-K1 cells, NO production by bFGF is Ca(2+) and MAP kinase independent, because it was not reverted by pretreatment with intracellular Ca(2+) chelators or MEK inhibitors. Translocation of the eNOS from the plasma membrane, where it is bound to caveolin 1, to the cytosol is the crucial step in the synthesis of NO. We demonstrate that the cytosolic translocation of eNOS is caused by increased synthesis of ceramide dependent by the bFGF activation of sphingomyelinase. Indeed, in the presence of the sphingomyelinase inhibitors D609 or desipramine, bFGF-dependent NO production is abrogated. To support this evidence we evaluated ceramide concentration using HPLC-electrospray ionization-mass spectrometry in controls and in bFGF-treated cells: after bFGF stimulation, a substantial increase in ceramide levels was observed. These data were further confirmed by the lack of NO production in response to fibroblast growth factor in fibroblasts derived from Niemann Pick patients who genetically lack the enzyme sphingomyelinase. In conclusion, ceramide in CHO-K1 cells is responsible for a novel Ca(2+)/calmodulin-independent mechanism for eNOS activation after fibroblast growth factor stimulation.

Animals↗