Mutations in the caveolin-3 gene cause autosomal dominant limb-girdle muscular dystrophy.

Limb-girdle muscular dystrophy (LGMD) is a clinically and genetically heterogeneous group of myopathies, including autosomal dominant and recessive forms. To date, two autosomal dominant forms have been recognized: LGMD1A, linked to chromosome 5q, and LGMD1B, associated with cardiac defects and linked to chromosome 1q11-21. Here we describe eight patients from two different families with a new form of autosomal dominant LGMD, which we propose to call LGMD1C, associated with a severe deficiency of caveolin-3 in muscle fibres. Caveolin-3 (or M-caveolin) is the muscle-specific form of the caveolin protein family, which also includes caveolin-1 and -2. Caveolins are the principal protein components of caveolae (50-100 nm invaginations found in most cell types) which represent appendages or sub-compartments of plasma membranes. We localized the human caveolin-3 gene (CAV3) to chromosome 3p25 and identified two mutations in the gene: a missense mutation in the membrane-spanning region and a micro-deletion in the scaffolding domain. These mutations may interfere with caveolin-3 oligomerization and disrupt caveolae formation at the muscle cell plasma membrane.

Induction of differentiation and apoptosis by interferon-gamma in human neuroblastoma cells in vitro as a dual and alternative early biological response.

Interferon-gamma (IFN-gamma) has a well known differentiation-promoting activity on several neuroblastoma (NB) cell lines and has also been reported to induce apoptosis in different cellular models. We have investigated the potential of IFN-gamma to trigger, besides differentiation, programmed cell death in NB cells and the relationship between these processes. Nine NB cell lines, characterized by different phenotypic and maturational features, were cultured in the presence of IFN-gamma (1000 IU/ml) for up to 5 days with either only one treatment at the start of the culture or renewing the culture medium (with or without IFN-gamma) every other day. Neuronal differentiation was assessed by evaluation of morphological changes and expression of mature cytoskeletal proteins, while apoptosis was evaluated at the desired times by fluorescent and electronic microscopy, DNA content analysis and DNA fragmentation assay. Our findings show that apoptosis is an early (mainly non post-differentiative) event and is much more evident following a single IFN-gamma administration. Moreover, IFN-gamma-triggered apoptosis is independent of the cellular phenotype (schwannian or neuronal) and appears to be mutually exclusive with respect to differentiation at the single cell level. Our results strengthen the potential of IFN-gamma as a promising therapeutic agent for NB.

Disruption of muscle basal lamina in congenital muscular dystrophy with merosin deficiency.

We studied three new cases of congenital muscular dystrophy (CMD) with homogeneous clinical and laboratory features, represented by congenital muscle hypotonia and weakness, early contractures, elevated serum CK, and dystrophic pattern at muscle biopsy, without clinical impairment of CNS. Merosin, the laminin isoform that contains the alpha 2 heavy chain, was absent in muscle fibers of all the patients by immunohistochemistry and by immunoblot. By electron microscopy, we found a severe disruption of muscle fiber basal lamina, but not of blood vessel basal lamina, which contains the laminin alpha 1 heavy chain isoform. This disruption may play a key role in the degeneration of muscle fibers and in the abnormal proliferation of connective tissue seen in CMD.

Combined defects of muscle phosphofructokinase and AMP deaminase in a child with myoglobinuria.

A 14-year-old boy with exercise-related myalgia and cramps had several episodes of myoglobinuria since early childhood. An episode at 2 years of age caused acute renal failure. Histochemical and biochemical analysis of muscle showed a combined defect of phosphofructokinase (PFK) and adenosine monophosphate (AMP) deaminase. DNA analysis showed that the patient was homozygous for a G-to-C substitution at codon 39 of the PFK gene (previously described in an Italian patient) and for the common mutation found in AMP deaminase deficiency.

Mutation in the CAV3 gene causes partial caveolin-3 deficiency and hyperCKemia.

Mutations in the caveolin-3 (CAV3) gene are associated with autosomal dominant limb-girdle muscular dystrophy (LGMD1C). The authors report a novel sporadic mutation in the CAV3 gene in two unrelated children with persistent elevated levels of serum creatine kinase (hyperCKemia) without muscle weakness. Immunohistochemistry and quantitative immunoblot analysis of caveolin-3 showed reduced expression of the protein in muscle fibers. Our data indicate that a partial caveolin-3 deficiency should be considered in the differential diagnosis of idiopathic hyperCKemia.

Very-long-chain acyl-coenzyme A dehydrogenase deficiency in a child with recurrent myoglobinuria.

A 9-year-old boy had recurrent episodes of myoglobinuria and normal urinary organic acid profile. Very-long-chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency was detected biochemically in cultured skin fibroblasts and confirmed by Western blot analysis. The patient had a distinctive plasma fatty-acid profile, which was present even between attacks. Early diagnosis of this disorder is important because of the apparently protective effect of an appropriate dietary regimen.

A novel missense mutation in the glycogen branching enzyme gene in a child with myopathy and hepatopathy.

We have identified a novel missense mutation in the gene for glycogen branching enzyme (GBE 1) in a 16-month-old infant with a combination of hepatic and muscular features, an atypical clinical presentation of glycogenosis type IV (GSD IV). The patient was heterozygous for a G-to-A substitution at codon 524 (R524Q), changing an encoded arginine (CGA) to glutamine (CAA), while the GBE1 gene on the other allele was not expressed. This case broadens the spectrum of mutations in patients with GSD IV and confirms the clinical and molecular heterogeneity of this disease.

Novel mutation in the CPT II gene in a child with periodic febrile myalgia and myoglobinuria.

We have identified a novel missense mutation in the carnitine palmitoyltransferase II (CPT II) gene in a child with CPT II deficiency characterized clinically by episodes of myalgia and myoglobinuria induced by intercurrent febrile illnesses. The patient was heterozygous for a G-to-A substitution at codon 487, changing an encoded glutamic acid to a lysine (E489K), while the other allele carried the common S113L mutation. This case enlarges the spectrum of mutations in patients with CPT II deficiency, and confirms the association of the S113L mutation with the muscular form.

Mitochondrial activity of orbicularis oris muscle in unilateral cleft lip patients.

To better evaluate the role of a possible mitochondrial alteration in the pathogenesis of cleft lip, we obtained and examined 38 orbicularis oris muscle specimens taken from the cleft margin of both cleft and noncleft sides of 10 unilateral cleft lip infants at the time of primary closure. Part of each sample was frozen in liquid nitrogen/cooled isopentane, while the remainder was fixed in 2.5% glutaraldehyde, postfixed in osmium tetroxide, and embedded in Araldyte resin. Ten-micrometer-thick sections were obtained from the frozen samples and stained for histologic (Gomori trichrome) and histochemical (adenosine triphosphatase, nicotinamide adenine dinucleotide-tetrazolium reductase, cytochrome c-oxidase, succinate dehydrogenase) techniques. Ultra-thin sections (70 to 100 nm) of the resin-embedded specimens were stained with uranyl acetate and lead cytrate and were examined with a Zeiss 109 transmission electron microscope operating at 80 kV. Muscular fiber-type ratio was found to be 19.2 percent type 1 and 80.8 percent type 2 fibers on the cleft side and 26.3 percent type 1 and 73.7 percent type 2 fibers on the noncleft side. We detected aspecific structural alterations, such as variations in the fiber size without fiber group atrophy or fiber-type grouping with the ATPase reaction, in all biopsies. Although Gomori trichrome revealed a dark staining and red granularity of the fibers, suggesting an increase in mitochondria activity, no ragged-red fibers or cytochrome c-oxidase-negative/succinate dehydrogenase-positive fibers were found. At the ultrastructural level, the mitochondrial morphology was always preserved, without inclusions or variations in size and/or shape. On the other hand, we invariably noticed an increase of the number of mitochondria, associated with abnormal glycogen deposits, in some areas of every specimen. Both of these two latter findings were regularly localized at the periphery of the sarcolemma, resembling the so-called lobulated fibers, an aspecific sign of muscular flogosis. Our findings, although excluding an inherent metabolic myopathy of orbicularis oris muscle in unilateral cleft lip patients, evinced both an increased oxidative metabolism and a generic inflammatory condition of that muscle, the nature of which must still be defined.

Report on a patient with congenital muscular dystrophy, hydrocephalus, Dandy-Walker malformation and leukodystrophy.

We report on a patient affected by congenital muscular dystrophy, severe psychomotor retardation, severe hypotonia, papillar hypoplasia and peculiar NMR pattern of hydrocephalus, Dandy-Walker malformation and leukodystrophy. These findings are intermediate between Walker-Walburg syndrome, Fukuyama disease and Occidental congenital muscular dystrophy. Our case focuses on the wide spectrum of congenital muscle dystrophy associated with central nervous system disease and on the difficulties of genetic counseling in these families.

Auriculo-condylar syndrome or new syndrome?

We describe a girl with peculiar auricular dysmorphism, renal agenesis and supernumerary rib. Some different diagnostic hypotheses are discussed.

[The role of liver in muscular dystrophy]. / Il ruolo del fegato nella distrofia muscolare.

Epidemiological or anamnestical data may either help or confuse the differential diagnosis of various diseases mainly characterized by asymptomatic hypertransaminasemia. Occasional finding of transaminase elevation may lead to suppose chronic or persistent hepatopathy, particularly when the patient seems to be asymptomatic and presents anamnestic data suggesting intoxication, acquired infection from blood derivatives, origin from geographic areas with high prevalence of viral hepatitis. However, the true existence of hepatic damage, concurrent to a myopathy, may be also related to the primitive diseases. There is evidence, in fact, that in the presence of muscular dystrophy, a disease caused by structural defects of muscular membranes, also hepatocytes show ultrastructural defects. The present work reports the cases of 5 children, hospitalized at the 1st Clinic of Infectious Diseases of the University of Genoa, affected by persistent hypertransaminasemia and showing anamnestical data suggesting hepatitis; histological findings of hepatitis were effectively shown in 3 patients after needle biopsy. All patients proved to be affected by muscular dystrophy. Hepatic damage results cannot be correlated to known causes of hepatopathy. During disease courses heralded by asthenia and hypertransaminasemia, differential diagnosis must take into account non-hepatic diseases, like muscular dystrophy. Although this disease mainly affects the muscle, also the liver seems to be involved, as suggested by histological changes found in some patients.

[Early myoclonic encephalopathy and spinal muscular atrophy type I]. / Encefalopatia mioclonica precoce ed atrofia muscolare spinale tipo I.

The authors describe the case of a floppy baby with the typical features of early myoclonic encephalopathy, represented by erratic and partial myoclonus of early onset and electroencephalographical suppression-burst pattern. Muscle biopsy made it possible to recognize an important neurogenic pattern, suggesting a severe form of spinal muscular atrophy. The association of these two disorders has never been reported.

Disorganization of dystrophin costameric lattice in Becker muscular dystrophy.

We studied by high-resolution immunofluorescence (HRI) and by confocal laser scanning optical microscopy (CLSOM) the costameric organization of dystrophin and vinculin at the surface membrane of muscle fibers from 4 young boys with Becker muscular dystrophy (BMD). By HRI, the surface membrane of normal fibers showed regular parallel bands encircling the fiber at the level of I and M band. In BMD fibers, the dystrophin bands were stretched apart, interrupted, or did not show the intermediate band encircling the M band. By CLSOM, computer reconstruction of muscle surface membrane showed disorganization of the costameric dystrophin lattice at the membrane level in BMD muscle, in contrast with the preservation of the costameric lattice organization of vinculin.

Severe dystrophinopathy in a patient with congenital hypotonia.

We studied a 2-year-old child with congenital hypotonia and proximal muscle weakness. There was no family history of neuromuscular disease. The child also had hypospadia. The central nervous system was apparently not involved. Muscle biopsy showed a dystrophic pattern and dystrophin was absent as shown by immunofluorescence and by Western blot. Vinculin and spectrin were also reduced, while merosin was normal in muscle fibers. This observation suggests that congenital hypotonia may be associated with a severe form of dystrophinopathy.

[Muscle phosphorylase deficiency in childhood. A case report]. / Il deficit di fosforilasi muscolare nell' età pediatrica. Contributo clinico.

Myophosphorylase deficiency or McArdle's disease is rarely recognized in childhood. The onset is generally in adolescence or in adult age with exercise intolerance, muscle cramps and myoglobinuria. Two siblings of 6 and 2 years of age are described. The first patient showed early fatigue and both had elevated CK levels. Morphological and biochemical studies of muscle biopsies revealed a defect of myophosphorylase.

[Cardiofacial syndrome. A case report]. / La sindrome cardio-facciale. Descrizione di un caso.

A case of cardio-facial syndrome with dysmorphic and asymmetric crying face, congenital heart defects, failure to thrive is described. The authors review the literature and underline the importance of asymmetric crying face as a marker of associated congenital anomalies.

Long-term survival in Stuve-Wiedemann syndrome: a neuro-myo-skeletal disorder with manifestations of dysautonomia.

Stuve-Wiedemann syndrome (SWS) is a multiple congenital anomalies syndrome mostly considered to have an early lethality. Only few patients have been reported with long survival; therefore, the clinical phenotype with age has not yet been clearly characterized. We report on two patients with SWS aged 12 and 3 years who have both the osteodysplastic symptoms of the entity as well as autonomic nervous system symptoms resembling familial dysautonomia: lack of corneal reflex and neuropathic keratitis, absence of fungiform papillae, ulcerations of the tongue, paradoxical sweating at low temperature, patellar hyporeflexia, and progressive scoliosis. The clinical and radiological similarities between patients with SWS and patients with Schwartz-Jampel syndrome have led to the suggestion that these two syndromes are a single entity. SWS and Schwartz-Jampel syndrome type II are now indeed considered to be identical, but the radiographic phenotype of SWS long survivors such as the presently reported patients justifies the distinction between SWS and the classical type of Schwartz-Jampel syndrome. An increased number of lipid droplets in muscle fibers and decreased muscle mitochondrial enzyme activities have been found in one patient, confirming a previously reported association between SWS and respiratory chain abnormalities.

Increased number of caveolae and caveolin-3 overexpression in Duchenne muscular dystrophy.

Caveolae are small pockets or invaginations localized at the plasma membrane. Caveolins are the principal protein components of caveolae and play an important structural role in the formation of caveolae membranes. Here, we studied by freeze fracture and immunological techniques the spatial organization of caveolae at the muscle cell plasma membrane and the expression of caveolin-3 in Duchenne muscular dystrophy (DMD) muscle fibers. In DMD muscle, we found an increased number of caveolae at the sarcolemma that corresponds to an overexpression of caveolin-3 by immunohistochemistry and by Western blot analysis. These findings suggest a possible role for caveolae and caveolin-3 in the pathogenesis of DMD.