Biomedical subjects

M Fanin

Publications and source records attributed to M Fanin.

At least 37 records · Page 2Linked to original sources

PubMed1999

The clinical spectrum of sarcoglycanopathies.

A group of 204 muscular dystrophy patients were screened for immunohistochemical and biochemical alpha-sarcoglycan defect and their DNA was analyzed for pathogenetic mutation in the four sarcoglycan genes. We identified 21 patients with alpha-, beta-, or gamma-sarcoglycan gene mutations. Patients with alpha-sarcoglycan gene mutations were clinically heterogeneous and showed either a rapid progressive or a late-onset slow course. In the slowly evolving group, a residual alpha-sarcoglycan protein was present, and its level correlated with a milder disease course and significant later inability to stand up from the floor (p < 0.00005). Most patients with beta- and gamma-sarcoglycan gene mutations presented a severe clinical course. There is a considerably different pattern of muscle involvement and disease course in these disorders, compared with dystrophinopathies.

Adolescent↗

PubMed1999

Heart involvement in muscular dystrophies due to sarcoglycan gene mutations.

Mutations in the sarcoglycan genes cause autosomal-recessive muscular dystrophies. Because sarcoglycan genes and their protein products are highly expressed both in skeletal and cardiac muscle, patients with these mutations might be expected to be at risk to develop dilated cardiomyopathy. We therefore studied 13 patients with alpha-, beta-, gamma-sarcoglycan gene mutations by thorough cardiological assessment. Electrocardiographic or echocardiographic abnormalities were observed in about 30% of cases showing a severe course of muscular dystrophy. No correlation was found between the presence of cardiac abnormalities and the type of mutation or sarcoglycan gene involved. The cardiac involvement was never severe, but it may be detected in early stages of the muscle disease. The absence of overt cardiac dysfunction may be due to lower sarcoglycan protein expression in cardiac than skeletal muscle or to less sarcolemmal instability at the myocardial level, possibly related to the different distribution of forces generated by contraction of the myocardium with respect to proximal limb-girdle muscles.

Adolescent↗

PubMed1999

Could utrophin rescue the myocardium of patients with dystrophin gene mutations?

The spontaneous up-regulation of utrophin, observed in dystrophin-deficient skeletal muscle fibers, may decrease the susceptibility of such fibers to necrosis. It has been reported that the utrophin-rescued double-mutant mdx mouse always develops a lethal cardiomyopathy. We report two patients with severe dilated cardiomyopathy due to dystrophin gene mutations: the first was a manifesting Duchenne muscular dystrophy carrier and the second a patient affected with moderate Becker muscular dystrophy. We studied their explanted heart specimen and/or endoImyocardial biopsies by immunohistochemistry and Western blot for both dystrophin and utrophin. Utrophin was found to be over-expressed in these specimens. Our results suggest that in these patients the up-regulation of utrophin in dystrophin-deficient cardiomyocytes was unable to prevent the development of life-threatening myocardial dysfunction. These findings seem to dampen the enthusiasm raised by the prospect of DMD treatment by utrophin rescue in skeletal muscle fibers, as the myocardium would still remain severely affected.

Adult↗

PubMed1999

McArdle's disease. The unsolved mystery of the reappearing enzyme.

We assessed the frequency of muscle fibers showing histochemical phosphorylase activity in 27 muscle biopsies from 25 unrelated patients with McArdle's disease and studied by immunohistochemistry and in situ hybridization whether the muscle-specific isoform was expressed. Positive phosphorylase fibers were observed in 19% of our series of biopsies. We show that the enzyme isoform expressed in regenerating fibers differs according to the genotype of patients: the muscle-specific isoform is transcribed and translated in patients with none of the described mutations in at least one allele of the myophosphorylase gene, whereas it is neither transcribed nor translated in patients with identified mutations in both alleles.

Adolescent↗

PubMed1999

Prenatal diagnosis in a family affected with beta-sarcoglycan muscular dystrophy.

We present here the first prenatal diagnosis in beta-sarcoglycan muscular dystrophy. The consultand was an 11-week pregnant mother of a girl diagnosed at the age of 3 years with beta-sarcoglycan muscular dystrophy based on the identification of two nonsense mutations in her beta-sarcoglycan gene and on the absence of beta-sarcoglycan in her muscle biopsy. The direct search for these mutations in the chorionic villus DNA of the fetus showed that the fetus did not inherit her sister mutations and thus, was reported as unaffected. We suggest that direct gene mutation detection is more reliable than linkage or protein study in the prenatal diagnosis of sarcoglycanopathies.

Child, Preschool↗

PubMed1998

Homozygous alpha-sarcoglycan mutation in two siblings: one asymptomatic and one steroid-responsive mild limb-girdle muscular dystrophy patient.

We describe a couple of siblings who have a homozygous mutation in the alpha-sarcoglycan gene and present a striking clinical difference in their phenotype; the brother is asymptomatic, and the sister is affected with mild limb-girdle muscular dystrophy. Drug therapy with a new steroid (deflazacort) was done over 6 months in the mild limb-girdle patient, and we observed objective benefit in muscle strength and in functional tests. Side effects were minimal. Immunohistochemistry for alpha-sarcoglycan showed reduced intensity of reaction in the limb-girdle dystrophy patient and was similar to normal in the asymptomatic case. A reduced amount of residual alpha-sarcoglycan protein level was found in their muscle biopsies. Unknown epigenetic or environmental factors may have an important role in determining protein and clinical phenotype expression. This is the first report of a patient with homozygous sarcoglycan gene mutation without overt muscle weakness in his adulthood. The spectrum of clinical phenotypes in sarcoglycanopathies is therefore wider than previously thought.

Adult↗

PubMed1998

Cardiac transplantation in a Duchenne muscular dystrophy carrier.

We report here for the first time the case of a symptomatic DMD carrier, who had a heart transplant for a severe dilated cardiomyopathy. Dystrophin immunohistochemistry, western blot and analysis of X-chromosome inactivation on leucocytes, and skeletal and cardiac muscle biopsies on the explanted heart were performed. The patient was a heterozygote for exons 50-52 deletion in the dystrophin gene. The number of dystrophin-deficient fibres in the heart was much higher than in skeletal muscle. On the other hand, the explanted heart showed a non-skewed pattern of X-chromosome inactivation, as in leukocytes and skeletal muscle. The adverse cardiac course may be explained by the absence of regeneration among cardiomyocytes.

Adult↗

PubMed1998

Laminin alpha2 muscular dystrophy: genotype/phenotype studies of 22 patients.

OBJECTIVE: To determine the number of primary laminin alpha2 gene mutations and to conduct genotype/phenotype correlation in a cohort of laminin alpha2-deficient congenital muscular dystrophy patients. BACKGROUND: Congenital muscular dystrophies (CMD) are a heterogeneous group of muscle disorders characterized by early onset muscular dystrophy and a variable involvement of the CNS. Laminin alpha2 deficiency has been reported in about 40 to 50% of cases of the occidental, classic type of CMD. Laminin alpha2 is a muscle specific isoform of laminin localized to the basal lamina of muscle fibers, where it is thought to interact with myofiber membrane receptor, such as integrins, and possibly dystrophin-associated glycoproteins. METHODS: Seventy-five CMD patients were tested for laminin alpha2 expression by immunofluorescence and immunoblot. The entire 10 kb laminin alpha2 coding sequence of 22 completely laminin alpha2-deficient patients was screened for causative mutations by reverse transcription (RT)-PCR/single strand conformational polymorphisms (SSCP) analysis and protein truncation test (PTT) analysis followed by automatic sequencing of patient cDNA. Clinical data from the laminin alpha2-deficient patients were collected. RESULTS: Thirty laminin alpha2-negative patients were identified (40% of CMD patients tested) and 22 of them were screened for laminin alpha2 mutations. Clinical features of laminin alpha2-deficient patients were similar, with severe floppiness at birth, delay in achievement of motor milestones, and MRI findings of white matter changes with normal intelligence. Loss-of-function mutations were identified in 95% (21/22) of the patients studied. SSCP analysis detected laminin alpha2 gene mutations in about 50% of the mutant chromosomes; PTT successfully identified 75% of the mutations. A two base pair deletion mutation at position 2,096-2,097 bp was present in 23% of the patients analyzed. CONCLUSIONS: Our data suggest that the large majority of laminin alpha2-deficient patients show laminin alpha2 gene mutations.

Base Sequence↗

PubMed1997

Mutations in the sarcoglycan genes in patients with myopathy.

BACKGROUND: Some patients with autosomal recessive limb-girdle muscular dystrophy have mutations in the genes coding for the sarcoglycan proteins (alpha-, beta-, gamma-, and delta-sarcoglycan). To determine the frequency of sarcoglycan-gene mutations and the relation between the clinical features and genotype, we studied several hundred patients with myopathy. METHODS: Antibody against alpha-sarcoglycan was used to stain muscle-biopsy specimens from 556 patients with myopathy and normal dystrophin genes (the gene frequently deleted in X-linked muscular dystrophy). Patients whose biopsy specimens showed a deficiency of alpha-sarcoglycan on immunostaining were studied for mutations of the alpha-, beta-, and gamma-sarcoglycan genes with reverse transcription of muscle RNA, analysis involving single-strand conformation polymorphisms, and sequencing. RESULTS: Levels of alpha-sarcoglycan were found to be decreased on immunostaining of muscle-biopsy specimens from 54 of the 556 patients (10 percent); in 25 of these patients no alpha-sarcoglycan was detected. Screening for sarcoglycan-gene mutations in 50 of the 54 patients revealed mutations in 29 patients (58 percent): 17 (34 percent) had mutations in the alpha-sarcoglycan gene, 8 (16 percent) in the beta-sarcoglycan gene, and 4 (8 percent) in the gamma-sarcoglycan gene. No mutations were found in 21 patients (42 percent). The prevalence of sarcoglycan-gene mutations was highest among patients with severe (Duchenne-like) muscular dystrophy that began in childhood (18 of 83 patients, or 22 percent); the prevalence among patients with proximal (limb-girdle) muscular dystrophy with a later onset was 6 percent (11 of 180 patients). CONCLUSIONS: Defects in the genes coding for the sarcoglycan proteins are limited to patients with Duchenne-like and limb-girdle muscular dystrophy with normal dystrophin and occur in 11 percent of such patients.

Adolescent↗

PubMed1997

Changes in skeletal muscle histology and metabolism in patients undergoing exercise deconditioning: effect of propionyl-L-carnitine.

To define the skeletal muscle abnormalities in patients undergoing exercise deconditioning and evaluate the metabolic effect of propionyl-L-carnitine (PLC), muscle biopsies were obtained from 28 patients with effort angina and 31 control subjects. Coronary artery disease patients received either placebo (n = 12), PLC (1.5 g i.v. followed by infusion of 1 mg/kg/min for 30 min, n = 10), or L-carnitine (1 g i.v. followed by infusion of 0.65 mg/kg/min for 30 min, n = 6) for 2 days. Exercise deconditioned patients treated with placebo showed normal muscle content of total carnitine and glycogen, and decrease in percentage of type 1 fibers (P < 0.01) and in the activity of citrate synthase (P < 0.05), succinate dehydrogenase (P < 0.05), and cytochrome oxidase (P < 0.05), as compared to controls. Both PLC and L-carnitine did not modify muscle fiber composition or enzyme activities, but significantly increased muscle levels of total carnitine by 42% and 31%, respectively (P < 0.05). Moreover, PLC significantly increased glycogen muscle content (P < 0.01), while the equimolar dose of L-carnitine did not. This effect, probably due to the anaplerotic activity of the propionic group of PLC, suggests that this drug may be effective in improving energy metabolism of muscles with impaired oxidative capacity.

Carnitine↗

PubMed1997

Genetic epidemiology of muscular dystrophies resulting from sarcoglycan gene mutations.

BACKGROUND: The autosomal recessive limb-girdle muscular dystrophies (LGMDs) are a group of genetically heterogeneous muscle diseases characterised by progressive proximal limb muscle weakness. Six different loci have been mapped and pathogenetic mutations in the genes encoding the sarcoglycan complex components (alpha-, beta-, gamma-, and delta-sarcoglycan) have been documented. LGMD patients affected with primary "sarcoglycanopathies" are classified as LGMD2D, 2E, 2C, and 2F, respectively. METHODS: A geographical area in north east Italy (2,319,147 inhabitants) was selected for a genetic epidemiological study on primary sarcoglycanopathies. Within the period 1982 to 1996, all patients living in this region and diagnosed with muscular dystrophy were seen at our centre. Immunohistochemical and immunoblot screening for alpha-sarcoglycan protein deficiency was performed on all muscle biopsies from patients with a progressive muscular dystrophy of unknown aetiology and normal dystrophin. Sarcoglycan mutation analyses were conducted on all patient muscle biopsies shown to have complete or partial absence of alpha-sarcoglycan immunostaining or a decreased quantity of alpha-sarcoglycan protein on immunoblotting. RESULTS: Two hundred and four patient muscle biopsies were screened for alpha-sarcoglycan protein deficiency and 18 biopsies showed a deficiency. Pathogenetic mutations involving one gene for sarcoglycan complex components were identified in 13 patients: alpha-sarcoglycan in seven, beta-sarcoglycan in two, gamma-sarcoglycan in four, and none in the delta-sarcoglycan gene. The overall prevalence of primary sarcoglycanopathies, as of 31 December 1996, was estimated to be 5.6 x 10(-6) inhabitants. CONCLUSION: The prevalence rate estimated in this study is the first to be obtained after biochemical and molecular genetic screening for sarcoglycan defects.

Adolescent↗

PubMed1996

Myocardial involvement is very frequent among patients affected with subclinical Becker's muscular dystrophy.

BACKGROUND: Several cases of Becker's muscular dystrophy (BMD) have been reported, which showed mild or subclinical skeletal muscle involvement with an overt dilated cardiomyopathy. Here, for the first time, a group of 28 patients with BMD who had a subclinical or benign myopathy have been studied through a thorough cardiological assessment. METHODS AND RESULTS: Each patient underwent ECG and echocardiographic examinations. Molecular analyses of the dystrophin gene and protein were performed. An unexpectedly high incidence of myocardial involvement was observed among patients affected with subclinical (72%) or benign (60%) BMD. The cardiac involvement appears to develop early from the right ventricle. Both the increase in left ventricular end-diastolic volume and the reduction in the ejection fraction appeared to be age related. Severe left ventricular dilation with reduced ejection fraction, which could be complicated by life-threatening arrhythmias, may occur. Contrary to previous reports, which indicated the involvement of 5'-end mutations in cardiomyopathies as a result of dystrophin gene alterations, this study shows that despite the apparent concentration of deletions in two regions (5'-end and exons 47 through 49), no general conclusions can be drawn regarding the involvement of specific gene mutations in the development of cardiomyopathy. CONCLUSIONS: Cardiomyopathy is the main clinical feature and complication in patients affected by subclinical or mild BMD. The cardiac manifestation is characterized by early right ventricular involvement and is later associated with left ventricular impairment. In mild BMD, myocardial damage may develop because the patients, who are unaware of a possible cardiac involvement, are still able to perform strenuous muscle exercise and, through pressure or volume overload, may induce mechanical stress, which is harmful for dystrophin-deficient myocardial cells.

Adolescent↗

PubMed1996

alpha-Sarcoglycan (adhalin) deficiency: complete deficiency patients are 5% of childhood-onset dystrophin-normal muscular dystrophy and most partial deficiency patients do not have gene mutations.

alpha-Sarcoglycan (adhalin), a 50-kDa component of the dystrophin-associated complex of proteins, participates in the stabilization of the myofiber plasma membrane in the membrane cytoskeleton. Deficiencies of alpha-sarcoglycan cause a subset of childhood-onset muscular dystrophy (SCARMD) cases. However, secondary deficiencies of alpha-sarcoglycan are common. To begin to establish the rates of false positives (secondary deficiencies), we used immunofluorescence to screen 30 Italian dystrophin-normal muscular dystrophy patient biopsies and identified 4 patients with partial alpha-sarcoglycan deficiency and 2 patients with complete deficiency. The entire alpha-sarcoglycan gene was screened for mutations using RT-PCR and SSCP of messenger RNA isolated from muscle biopsies in each of the six patients. Aberrant SSCP conformers and novel mutations were found only in the two complete immunohistochemical deficient patients. One patient was homozygous for a R34H amino acid substitution, while the other was a compound heterozygote (R77C, D97G). These three missense mutations, with additional mutations we and others have previously described, are all localized in the extracellular domain of alpha-sarcoglycan, and most result in the loss or gain of a positively charged amino acid. These data have strong implications for structure/function maps of the alpha-sarcoglycan molecule. Our results suggest that most patients showing partial alpha-sarcoglycan deficiency exhibit this as a secondary consequence of genetically distinct disorders. In support of this, we show biochemical data indicating that secondary deficiency patients show decreased immunostaining with antibodies directed against alpha-sarcoglycan, while having nearly normal quantities of alpha-sarcoglycan protein on immunoblot. This data also suggests that approximately 5% of childhood-onset dystrophin-normal muscular dystrophy patients will show a primary alpha-sarcoglycan deficiency.

Base Sequence↗

PubMed1996

Duchenne phenotype with in-frame deletion removing major portion of dystrophin rod: threshold effect for deletion size?

In a 9-year-old boy with Duchenne muscular dystrophy we found a large in-frame deletion, spanning exons 10 to 53 of the dystrophin gene. The deletion removed almost all of the central rod domain of dystrophin. Using carboxyterminal dystrophin antibodies the immunohistochemical reaction was normal in all muscle fibers. In immunoblot studies we found dystrophin of abnormal size (160 kDa) and normal amount (about 100%). The immunochemical features and the reading frame deduced from DNA analysis are usually associated with Becker muscular dystrophy, but the clinical characteristics were those of the severe Duchenne phenotype. All the cases of in-frame dystrophin deletions reported so far, which involved more than 36 exons, invariably resulted in a severe phenotype. Therefore, a threshold effect for dystrophin length may be reasonably suspected. Very short dystrophin molecules might induce a severe disarray of the dystrophin network.

Blotting, Western↗

PubMed1996

Brain alterations in the classical form of congenital muscular dystrophy. Clinical and neuroimaging follow-up of 12 cases and correlation with the expression of merosin in muscle.

In the classical form of congenital muscular dystrophy (CMD), subclinical brain involvement is frequent. In order to establish the natural evolution of CNS alterations in this type of CMD, the cerebral functions of 12 cases were examined longitudinally for a mean period of 8 years. There were 7 boys and 5 girls, with a mean age of 5 years at first evaluation and 13 at the last one. Merosin expression in muscle fiber basement membrane, evaluated in 10 of them, was normal in 6 and deficient in 4. CNS conditions were followed up by repeated neuropsychiatric examinations, intelligence tests, EEG and brain CT scan and/or MRI. Eight of the 12 patients (including the 4 with merosin-deficiency) had normal intelligence, while 4 had mild to moderate mental retardation: in all the intellectual ability was unchanged during the follow-up study. CT scan detected minor brain alterations in 9 patients: 6 of these, the 4 with merosin deficiency and 2 others in whom merosin was not evaluated, presented leukoencephalopathy: on neuroimaging reappraisal it was unchanged in 3, improved in 2 and worse in 1 (a merosin-deficient case). Cerebellar alterations or mild ventricular dilatation were detected in 8 cases, including 3 merosin-non-deficient ones: these abnormalities were unchanged at the last study by CT and MRI, as were the normal neuroimaging findings observed in 3 other cases. Overall, during our study the brain alterations found in classical CMD showed a stationary or an improving course; progressive worsening was observed only in 1 of 4 merosin-deficient cases with leukoencephalopathy.

Adolescent↗

PubMed1996

Molecular characterization of myophosphorylase deficiency in a group of patients from northern Italy.

We studied a group of 14 patients from Northern Italy with myophosphorylase deficiency. The disease presented considerable clinical and biochemical heterogeneity, which was reflected at the molecular level. The clinical presentation was typical in 3 patients, mild in 7 (exercise intolerance), and severe in 4 (fixed weakness). Enzyme activity was undetectable in 10 patients, below 3% of control in 3, and 13% of control in one. Enzymatic protein was detectable immunologically only in 1 patient. Myophosphorylase mRNA was present in 8 patients, but in 7 of them it was reduced in amount. Two patients were homozygous for the common nonsense R49X mutation, 5 were heterozygous. Two missense mutations not previously observed were identified in this group of patients. The frequency of alleles with the R49X mutation was significantly lower in this group of patients than in previously reported series. Myophosphorylase deficiency is genetically heterogeneous even among patients living in a small region and with a common ethnic background.

Adolescent↗

PubMed1996

Prognostic factors in mild dystrophinopathies.

One hundred twenty five patients from 105 families were considered, showing in-frame intragenic deletion or duplication of the dystrophin gene and/or abnormal dystrophin on muscle biopsy. According to clinical status of patients, the affection was classified as subclinical, benign, moderate or severe. Significant decrease of dystrophin abundance was observed with increasing clinical severity (p < 0.05). Detailed clinical data were available in 68 patients in whom a long-term follow-up (6-39 years) was obtained. Functional performance at different ages and disease endpoints were recorded in order to analyze the rate of disease progression. We identified three different disease courses: stable, slow and rapid progression. We observed a significantly lower level of dystrophin and immunohistochemical score (p < 0.05 vs. the other courses) in patients with rapid course. Deletion or duplication in the 5' end of the gene was associated with poor prognosis. Prognosis was substantially better, showing a stable course, in patients with large deletions or duplications in the proximal rod region. These subjects often suffered from a cramps/myalgia syndrome or experienced rhabdomyolisis. Cardiac involvement was detected in 65% of cases. A significant increase of right ventricular volume was seen in all clinical groups (p < 0.05). A left ventricular dilation was observed in 25% and a decreased ejection fraction in 29% of our patients. The reduction of ejection fraction and the increase of left ventricular volume were age-related. Since sudden death may occur as a consequence of cardiomyopathy, severe left ventricular dysfunction in dystrophinopathic patients is another important adverse prognostic factor, although not always directly correlated with skeletal muscle impairment.

Adolescent↗

PubMed1996

Cardiac and respiratory involvement in advanced stage Duchenne muscular dystrophy.

This study aimed to describe myocardial involvement, respiratory impairment and pulmonary blood flow abnormalities in advanced-stage Duchenne muscular dystrophy (DMD). Twenty-one wheelchair-bound patients, aged from 10 to 24 yr, underwent electrocardiographic and echocardiographic examination, conventional spirometry, diurnal arterial blood gas analysis, and nocturnal polysomnography (SaO2 monitoring). Diagnosis was confirmed by neurological examination, dystrophin analysis at protein and DNA level. Patients were classified into two groups: group A normoxemic (14 cases) and group B with nocturnal hypoxemia (seven cases). Group A was further split into two subgroups, one without, and one with, left ventricular dilation (A1 = nine patients, end diastolic volume (EDV) = 51 ml m-2, ejection fraction (EF) = 56 per cent; A2 = five patients, EDV = 112 ml m-2, EF = 32 per cent; P < 0.05). Left ventricular regional wall motion abnormalities were found in 55, 40, and 43 per cent of groups A1, A2, and B patients respectively. Analysis of pulsed Doppler pulmonary data highlighted a significant reduction in corrected time to peak velocity in group B patients, when compared with control, A1, and A2 groups respectively. In group A, we observed a direct correlation between ejection fraction and corrected time-to-peak velocity. Two patterns of cardiac involvement may be recognized in advanced-stage DMD: left ventricular wall motion abnormalities and dilated cardiomyopathy. Doppler data which could suggest pulmonary hypertension may be observed in patients with dilated cardiomyopathy, and in patients with nocturnal hypoxemia. Therefore, in the management of advanced-stage DMD, a careful diagnosis of the heart-lung relationship should be performed, and both conventional treatment of heart failure and ventilatory therapy are necessary to improve the quality of life and survival in these patients.

Adolescent↗