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Biomedical subjects

E Zammarchi

Publications and source records attributed to E Zammarchi.

At least 55 records · Page 3Linked to original sources
PubMed1997

RNA metabolism in myotonic dystrophy: patient muscle shows decreased insulin receptor RNA and protein consistent with abnormal insulin resistance.

Myotonic dystrophy is a dominantly inherited clinically variable multisystemic disorder, and has been found to be caused by heterozygosity for a trinucleotide repeat expansion mutation in the 3' untranslated region of a protein kinase gene (DM kinase). The mechanisms by which the expanded repeat in DNA results in a dominant biochemical defect and the varied clinical phenotype, is not known. We have recently proposed a model where disease pathogenesis may occur at the RNA level in myotonic dystrophy: the mutant DM kinase RNA with the expansion mutation may disrupt cellular RNA metabolism in some general manner, as evidenced by defects in RNA processing of the normal DM kinase gene in heterozygous patients (dominant negative RNA mutation). Here we further test this hypothesis by measuring RNA metabolism of other genes in patient muscle biopsies (nine adult onset myotonic dystrophy patients, two congenital muscular dystrophy patients, four normal controls, and four myopathic controls). We focused on the insulin receptor gene because of the documented insulin resistance of DM patients. We show that there is a significant decrease in insulin receptor RNA in both total RNA and RNA polyA+ pools relative to normal and myopathic control muscles (P < 0.002), measured relative to both dystrophin RNA and muscle sodium channel RNA. We also show reductions in insulin receptor protein. Our results reinforce the concept of a generalized RNA metabolism defect in myotonic dystrophy, and offer a possible molecular mechanism for the increased insulin resistance observed in many myotonic dystrophy patients.

Adolescent↗
PubMed1997

Asymptomatic dystrophinopathy.

A 4-year-old girl was referred for evaluation for a mild but persistent serum aspartate aminotransferase (AST) elevation detected incidentally during routine blood screening for a skin infection. Serum creatine kinase activity was found to be increased. Immunohistochemical study for dystrophin in her muscle biopsy showed results consistent with a carrier state for muscular dystrophy. Molecular work-up showed the proposita to be a carrier of a deletion mutation of exon 48 of the dystrophin gene. Four male relatives also had the deletion mutation, yet showed no clinical symptoms of muscular dystrophy (age range 8-58 yrs). Linkage analysis of the dystrophin gene in the family showed a spontaneous change of an STR45 allele, which could be due to either an intragenic double recombination event, or CA repeat length mutation leading to identical size alleles. To our knowledge, this is the first documentation of an asymptomatic dystrophinopathy in multiple males of advanced age. Based on molecular findings, this family would be given a diagnosis of Becker muscular dystrophy. This diagnosis implies the development of clinical symptoms, even though this family is clearly asymptomatic. This report underscores the caution which must be exercized when giving presymptomatic diagnoses based on molecular studies.

Adolescent↗
PubMed1997

Neonatal onset of hyperornithinemia-hyperammonemia-homocitrullinuria syndrome with favorable outcome.

We report on a neonate with hyperammonemic coma in whom hyperornithinemia-hyperammonemia-homocitrullinuria syndrome was diagnosed. Appropriate treatment led to rapid clinical and metabolic improvement. The incorporation of 14C-ornithine on cultured fibroblasts confirmed the diagnosis. At the age of 18 months, the patient is in excellent clinical condition.

Amino Acid Metabolism, Inborn Errors↗
PubMed1997

The X-linked gene G4.5 is responsible for different infantile dilated cardiomyopathies.

Barth syndrome (BTHS) is an X-linked disorder characterized clinically by the associated features of cardiac and skeletal myopathy, short stature, and neutropenia. The clinical manifestations of the disease are, in general, quite variable, but cardiac failure as a consequence of cardiac dilatation and hypertrophy is a constant finding and is the most common cause of death in the first months of life. X-linked cardiomyopathies with clinical manifestations similar to BTHS have been reported, and it has been proposed that they may be allelic. We have recently identified the gene responsible for BTHS, in one of the Xq28 genes, G4.5. In this paper we report the sequence analysis of 11 additional familial cases: 8 were diagnosed as possibly affected with BTHS, and 3 were affected with X-linked dilated cardiomyopathies. Mutations in the G4.5 gene were found in nine of the patients analyzed. The molecular studies have linked together what were formerly considered different conditions and have shown that the G4.5 gene is responsible for BTHS (OMIM 302060), X-linked endocardial fibroelastosis (OMIM 305300), and severe X-linked cardiomyopathy (OMIM 300069). Our results also suggest that very severe phenotypes may be associated with null mutations in the gene, whereas mutations in alternative portions or missense mutations may give a "less severe" phenotype.

Abnormalities, Multiple↗
PubMed1996

Early-infantile galactosialidosis: clinical, biochemical, and molecular observations in a new patient.

Few patients with the early-infantile form of galactosialidosis have been described to date. Presented here is the first Italian case. Fetal hydrops was detected by ultrasound at week 24 of gestation. At birth, the infant presented with hypotonia, massive edema, a flattened coarse facies, telangiectasias, and hepatosplenomegaly, but no dysostosis multiplex. The patient died 72 days postpartum. Excessive sialyloligosaccharides in urine, as well as vacuolation of lymphocytes and eosinophilic granulocytes in peripheral blood, were indicative of a lysosomal storage disease. In the patient's fibroblasts, both alpha-neuraminidase and beta-galactosidase activities were severely reduced, and cathepsin A activity was < 1% of control levels, confirming the biochemical diagnosis of galactosialidosis. However, in contrast to previously reported early-infantile cases, a normal amount of protective protein/cathepsin A mRNA was detected on Northern blots. This mutant transcript was translated into a precursor protein that was not processed into the mature enzyme and lacked both protective and catalytic activities.

Carboxypeptidases↗
PubMed1996

Different neurologic outcomes in two patients with neonatal hyperinsulinemic hypoglycemia.

The authors report the cases of two patients with neonatal onset of hypoketotic hypoglycemia with hyperinsulinism and a poor response to diazoxide. Pancreatic venous sampling showed a diffuse pancreatic hyperplasia in one patient and a focal lesion in the other. The second patient, diagnosed after a significant delay, suffered severe long-term neurological sequelae, despite having more limited hyperplasia; the brain MRI also showed severe pathological changes in cortex and white matter, predominantly in the parieto-occipital region. Early and accurate diagnosis is critical in these patients in whom hypoglycemia is compounded by a lack of the ketone bodies which represent a vital alternative source of energy for the central nervous system.

Atrophy↗
PubMed1996

Biochemical evaluation of a patient with a familial form of leucine-sensitive hypoglycemia and concomitant hyperammonemia.

A case of a child with recurrent episodes of severe hypoglycemia since the age of 6 months is reported. Biochemical evaluation extended to the first-degree relatives is consistent with a familial form of hypoglycemia due to a leucine-sensitive hyperinsulinism. In addition, this patient has a persistent elevation of serum ammonia levels of uncertain etiology that is more pronounced after meals. Urea cycle defects, organic acidurias, and beta-oxidation defects have been ruled out, as well as a possible excessive deamination of glucogenetic amino acids. This unexpected hyperammonemia, which was also detected in the mother, might be related to leucine hypersensitivity.

Adult↗
PubMed1996

Molecular and biochemical analysis of protective protein/cathepsin A mutations: correlation with clinical severity in galactosialidosis.

Mutations in the gene encoding lysosomal protective protein/cathepsin A (PPCA) are the cause of the lysosomal disorder galactosialidosis (GS). Depending on age of onset and severity of the symptoms, patients present with either an early infantile (EI), a late infantile (LI), or a juvenile/adult (J/A) form of the disease. To study genotype-phenotype correlation in this disorder, we have analyzed the mutations in the PPCA gene of eight clinically different patients. In two EI and one J/A patient, we have identified four novel point mutations (Val104Met, Leu208Pro, Gly411Ser and Ser23Tyr), that prevent phosphorylation and, hence, lysosomal localization and maturation of the mutant precursors. Two amino acid substitutions (Phe412Val and Tyr221Asn) are shared by five LI patients. These mutations appear to be pathognomonic for this phenotype, and determine the clinical outcome depending on whether they are present together or in combination with other mutations. The latter include a single base deletion and a novel amino acid change (Met378Thr), which generates an additional glycosylation site. Within the LI group, patients carrying the Phe412Val mutation are clinically more severe than those with the Tyr221Asn substitution. This is in agreement with the biochemical behavior of the Asn221-mutant protein, that is, like the Phe412Val protein, phosphorylated, routed to lysosomes and proteolytically processed, but its intralysosomal stability is intermediate between that of wild-type PPCA and Val412-PPCA. Overall, these results may explain the clinical heterogeneity observed in GS patients and may help to correlate mutant allelic combinations with specific clinical phenotypes.

Alleles↗
PubMed1996

Cryptogenic hepatitis masking the diagnosis of ornithine transcarbamylase deficiency.

We describe three children with transaminase elevations and hepatic insufficiency who were given the diagnosis of cryptogenic hepatitis after the more common viral and metabolic diseases of the liver had been excluded. However, further laboratory investigations showed hyperammonemia, low blood urea levels, elevated plasma glutamine levels, and low citrulline levels. Urinary excretion of orotic acid was higher than normal, with absent urinary homocitrulline and normal fractional tubular reabsorption of lysine, ornithine, and arginine. These findings suggest the diagnosis of ornithine transcarbamylase deficiency. We emphasize the importance of investigating possible urea cycle disorders by determining ammonia plasma levels, both at baseline and after a protein load; urinary and plasma amino acids; and urinary orotic acid in all patients with liver disease of indeterminate etiology.

Absorption↗
PubMed1995

The preventive effect and duration of action of two doses of inhaled furosemide on exercise-induced asthma in children.

BACKGROUND: Exercise-induced asthma can be prevented by treatment with inhaled furosemide. OBJECTIVE: In this study we evaluated the effect and duration of action of two doses (15 and 30 mg) of inhaled furosemide in prevention of exercise-induced asthma in children. METHODS: Ten children with exercise-induced asthma (8 boys and 2 girls, aged 6 to 13 years) were included in the study. Each patient was tested with three treatment regimens (placebo, 15 mg of furosemide, and 30 mg of furosemide) in random order on 3 separate days. Patients performed exercise challenges on a treadmill at 20 minutes and 1, 2, 3, and 6 hours after each treatment. Pulmonary function, urinary output, and fluid intake were monitored. RESULTS: Both doses of furosemide had a significantly greater protective effect than placebo, but there was no significant difference between the two doses of furosemide. The higher dose of furosemide was associated with increased urinary output and had a longer duration of action. CONCLUSION: A 30 mg dose of furosemide is more effective for treatment of exercise-induced asthma in terms of duration but has a significant diuretic effect.

Administration, Inhalation↗
PubMed1995

An X:autosome translocation stabilizes truncated dystrophin: implications for lack of truncated dystrophins in Duchenne muscular dystrophy.

We report a 5-year-old girl with clinical symptoms of typical Duchenne muscular dystrophy in males. The girl showed dramatic elevations of serum creatine kinase, and muscle biopsy histopathology consistent with a severe dystrophic myopathy. Cytogenetic analysis revealed an X:22 translocation (46,X,t [X;22] [p21.2;11.2]). Dystrophin immunofluoresence studies showed strong membrane immunostaining of dystrophin with antibodies directed against the amino terminus of the protein, but vastly reduced immunostaining with carboxyl-terminal antibodies. Immunoblot studies showed a major immunoreactive protein of approximately 350 kDa at approximately 20% levels. Nested RT-PCR analysis of the dystrophin mRNA in the patient's muscle showed the RNA to be positive for primers covering the first 85% of the dystrophin coding sequence, and negative for the carboxyl-terminal 15%. Taken together, our data suggests that the translocation breakpoint occurs towards the 3' end of the gene. The translocated dystrophin gene is still expressed into a truncated dystrophin protein associated with the plasma membrane. Our results are consistent with the translocation resulting in a more stable abnormal dystrophin mRNA.

Antibodies, Monoclonal↗
PubMed1995

Transient neonatal nonketotic hyperglycinemia: a 13-year follow-up.

We report on a patient with transient nonketotic hyperglycinemia (NKH). Onset, clinical features, biochemical and electroencephalographic findings were consistent with neonatal nonketotic hyperglycinemia. The normalization of clinical, biochemical and electroencephalographic features on day 9 without specific therapy suggested a transient form. At the last follow-up the girl was 13 years old, had a normal mental development, no EEG abnormalities or neurological deficits.

Amino Acid Metabolism, Inborn Errors↗
PubMed1995

Mother-to-infant transmission of hepatitis C virus.

Anti-hepatitis C virus (HCV) antibodies and HCV-RNA were measured in the sera of 22 anti-HCV positive, HIV-1 negative mothers and their infants. ELISA and RIBA II were used for anti-HCV determination. HCV-RNA was measured by a nested polymerase chain reaction. HCV-RNA was found in 12 of 22 mothers. All 22 children were followed for 12 months. All were anti-HCV positive by the fourth month; 18 became anti-HCV negative between the 8th and 12th month. HCV-RNA was detected in 5 of 22 infants in the fourth month. They remained HCV-RNA positive. All children born to HCV-RNA negative mothers were HCV-RNA negative while 5 of 12 babies born to HCV-RNA positive mothers were infected. All five infected babies were born to mothers infected through transfusions or drug use. ALT levels in mothers seemed to have no effect on mother-to-infant transmission. Hence evidence for perinatal transmission of HCV from HCV-RNA positive mothers was demonstrated in the present study.

Adult↗
PubMed1994

Insertion of a T next to the donor splice site of intron 1 causes aberrantly spliced mRNA in a case of infantile GM1-gangliosidosis.

The lysosomal storage disorders GM1-gangliosidosis and Morquio B syndrome are caused by a complete or partial deficiency of acid beta-galactosidase. Here, we have characterized the mutation segregating in a family with two siblings affected by the severe infantile form of GM1-gangliosidosis. In total mRNA preparations derived from the patients' fibroblasts at least two aberrantly spliced beta-galactosidase transcripts (1 and 2) have been identified. Both transcripts contain a 20 nucleotide (nt) insertion derived from the 5' end of intron 1 of the beta-galactosidase gene. Furthermore, in transcript 2 sequences encoded by exon II are deleted during the splicing process. Comparison of the 20-nt insertion with wild-type intronic sequences indicated that in the genomic DNA of the patients an extra T nucleotide is present immediately downstream of the conserved GT splice donor dinucleotide of intron 1. Both patients are homozygous for the T nucleotide insertion. We propose that this single base insertion is the mutation responsible for aberrant splicing of beta-galactosidase pre-mRNA, giving rise to transcripts that cannot encode a normal protein.

Base Sequence↗
PubMed1994

Prenatal diagnosis by minisatellite analysis in Italian families with phenylketonuria.

A polymorphic short tandem repeat (STR) in intron 3 (Goltsov et al., 1993) and a variable number of tandem repeats (Hind III-VNTR) flanked by two constant Hind III sites (Golstov et al., 1992) have been recently identified in the human phenylalanine hydroxylase (PAH) gene. These polymorphisms are easily detected by the polymerase chain reaction (PCR) and gel electrophoresis. We report on the use of these two novel polymorphisms in three Italian families with pregnancies at risk for classical phenylketonuria (PKU). A carrier status for PKU was ascertained in two fetuses; the third family refused prenatal diagnosis, although informativeness was shown to be complete.

Alleles↗