Cardiac treatment in neuro-muscular diseases.

The authors have been treating heart involvement in muscle dystrophy since 1978. However, this study aimed to define recent therapeutic protocols, evaluating the results of cardiac treatment, performed between 1st February 2004 and 31st July, 2006. In this period, 100 Becker, 136 Duchenne, 44 Limb-girdle and 116 Steinert patients were treated. In that same period, a large group of MD patients refusing cardiac therapy have also been followed. All patients had previously been classified in the appropriate stage of cardiomyopathy and examined at least twice every year and even every week if presenting heart failure. The results show the usefulness of the recent protocols of treatment of cardiac involvement in muscle dystrophy patients.

Extensive scanning of the calpain-3 gene broadens the spectrum of LGMD2A phenotypes.

BACKGROUND: The limb girdle muscular dystrophies (LGMD) are a heterogeneous group of Mendelian disorders highlighted by weakness of the pelvic and shoulder girdle muscles. Seventeen autosomal loci have been so far identified and genetic tests are mandatory to distinguish among the forms. Mutations at the calpain 3 locus (CAPN3) cause LGMD type 2A. OBJECTIVE: To obtain unbiased information on the consequences of CAPN3 mutations. PATIENTS: 530 subjects with different grades of symptoms and 300 controls. METHODS: High throughput denaturing HPLC analysis of DNA pools. RESULTS: 141 LGMD2A cases were identified, carrying 82 different CAPN3 mutations (45 novel), along with 18 novel polymorphisms/variants. Females had a more favourable course than males. In 94% of the more severely affected patient group, the defect was also discovered in the second allele. This proves the sensitivity of the approach. CAPN3 mutations were found in 35.1% of classical LGMD phenotypes. Mutations were also found in 18.4% of atypical patients and in 12.6% of subjects with high serum creatine kinase levels. CONCLUSIONS: A non-invasive and cost-effective strategy, based on the high throughput denaturing HPLC analysis of DNA pools, was used to obtain unbiased information on the consequences of CAPN3 mutations in the largest genetic study ever undertaken. This broadens the spectrum of LGMD2A phenotypes and sets the carrier frequency at 1:103.

Cardiomyopathies: diagnosis of types and stages.

Primary cardiomyopathies have as dominant feature the involvement of heart muscle itself. They are not the result of other diseases and should be defined as diseases of heart muscle not consequent to disorders of other parts of the cardiovascular apparatus. Most of them are consequent to genetic defects and can be subdivided into three major groups: isolated, associated with skeletal muscle diseases, associated with neurological disorders. Primary cardiomyopathies show an evolution from mild to more severe stages. Four types of cardiomyopathies are classically described: dilated, hypertrophic, restrictive and arrhythmogenic. However, from a clinical point of view, it is possible to distinguish seven stages: pre-clinical, prevalently arrhythmogenic, prevalently pseudo-hypertrophic, spotty fibrotic, restrictive, dilated and refractory heart failure. In the course of their evolution, cardiomyopathies can shift from a clinical picture to another, consequently requiring frequent examinations of patients in order to adjust their treatment.

Deflazacort in Duchenne muscular dystrophy: a comparison of two different protocols.

We compare the long-term benefits and side effects of deflazacort using two treatment protocols from Naples (N) and Toronto (T). Boys with Duchenne muscular dystrophy between the ages of 8 and 15 years and who had four or more years of deflazacort treatment were reviewed. Diagnostic criteria included males with proximal muscle weakness evident before 5 years, increased serum creatine kinase and genetic testing and/or a muscle biopsy consistent with Duchenne muscular dystrophy. Thirty-seven boys were treated with protocol-N using deflazacort at a dose of 0.6 mg/kg per day for the first 20 days of the month and no deflazacort for the remainder of the month. Boys with osteoporosis received daily vitamin D and calcium. Deflazacort treatment started between 4 and 8 years of age. Thirty-two were treated with protocol-T using deflazacort at a dose of 0.9 mg/kg per day, plus daily vitamin D and calcium. Treatment started between 6 and 8 years of age. All boys were monitored every 4-6 months. The results were compared with age-matched controls in the two groups (19 for protocol-N and 30 for protocol-T). For the boys treated with protocol-N, 97% were ambulatory at 9 years (control, 22%), 35% at 12 years (control, 0%), 25% at 15 years (control, 0%). For the 32 boys treated with protocol-T, 100% were ambulatory at 9 years (control, 48%), 83% at 12 years (control, 0%) and 77% at 15 years (control, 0%). No aids or leg braces were used for ambulation. In boys 13 years and older, a scoliosis of >20 degrees developed in 30% of the boys on protocol-N, 16% on protocol-T and 90% of controls. For protocol-N, no cataracts were observed while in protocol-T, 30% of boys had asymptomatic cataracts that required no treatment. Fractures occurred in 19% (control 16%) of boys on protocol-N and 16% (control, 20%) of boys on protocol-T. This report illustrates: (a) the importance of collaborative studies in developing treatment protocols in Duchenne muscular dystrophy and (b) the long-term beneficial effects of deflazacort treatment in both protocols. However, the protocol-T seems to be more effective and frequently is associated with asymptomatic cataracts.

Gentamicin administration in Duchenne patients with premature stop codon. Preliminary results.

Aim of the study was to investigate whether the administration of gentamicin could restore dystrophin expression in striated muscles of patients with Duchenne muscular dystrophy caused by premature stop codon, as reported in mdx mice. Four Duchenne patients, still ambulant or in wheelchair stage for less than 4 months, selected among those with point mutations resulting in premature stop codons, received two 6-day cycles of gentamicin sulfate, at an interval of 7 weeks, according to the protocol approved by the Ethics Committee of the Second University of Naples. A muscle biopsy was performed after the second cycle of administration; the specimens were analysed by both immuno-histochemistry and Western blotting. Skeletal muscle changes were monitored by dynamic tests and Creatine Kinase values; at the beginning and end of treatment, cardiac and respiratory status was evaluated by electrocardiography, echocardiography, acoustic densitometry and vital capacity. Side-effects such as nephrotoxicity and ototoxicity were also monitored. Three out of four patients, who had the most permissive UGA as stop codon, showed positive results. In one patient, there was a dramatic re-expression of dystrophin by both immuno-histochemistry and Western blot; in two patients, dystrophin positive fibres were seen by the antibody to the rod domain with immuno-histochemistry; the fourth patient, with UAA as stop codon, showed no expression of dystrophin at all. These results suggest that gentamicin is able to recover dystrophin expression in a subset of Duchenne patients with nonsense mutations, raising the possibility of the first pharmacological treatment for muscular dystrophy.

ST-segment displacement in Duchenne muscular dystrophy: myocardial necrosis or apoptosis?

An electrocardiographic pattern resembling myocardial infarction is a rare condition in Duchenne muscular dystrophy. We report the case of a Duchenne boy, aged 12 years and 7 month, who, during a programmed examination, showed electrocardiographic signs of ST segment elevation, without symptoms usually accompanying myocardial infarction (chest pain, dyspnoea, sweating). The biological markers of myocardial damage became positive on the 2nd day and recovered on the 5th day. Clinical features of this uncommon pattern are described, with the retrospective evaluation of similar cases from personal records. The differential diagnosis between myocardial necrosis and apoptosis is discussed.

Evaluation of cardiac and respiratory involvement in sarcoglycanopathies.

Sarcoglycanopathies constitute a subgroup of limb-girdle recessive muscular dystrophies due to defects in sarcoglycan complex that comprises five distinct transmembrane proteins called alpha-, beta-, gamma-, delta-and epsilon-sarcoglycans. As it is well known that sarcoglycans are expressed both in heart and in skeletal muscles and a complete deficiency in delta-sarcoglycan is the cause of the Syrian hamster BIO.14 cardiomyopathy, we studied cardiac and respiratory involvement in 20 patients with sarcoglycanopathies by clinical, electrocardiographic, echocardiographic, scintigraphic and spirometric assessments. A normal heart function was found in 31.3% of all patients; a preclinical cardiomyopathy in 43.7%; an arrhythmogenic cardiomyopathy in 6.3% and initial signs of dilated cardiomyopathy in 18.7%. In one patient the data were examined retrospectively. No correlation was found between cardiac and skeletal muscle involvement. With reference to the type of sarcoglycanopathy, signs of hypoxic myocardial damage occurred in beta-, gamma- and delta-sarcoglycanopathies, while initial signs of a dilated cardiomyopathy in gamma- and delta-sarcoglycanopathies were found. A normal respiratory function was observed in 23.5% of all patients, a mild impairment in 35.4%, a moderate impairment in 29.4%, and a severe impairment in 11.7%.

Autonomic nervous system imbalance and left ventricular systolic dysfunction as potential candidates for arrhythmogenesis in Becker muscular dystrophy.

We evaluated the arrhythmic profile in a population of 20 Becker muscular dystrophy (BMD) patients searching for possible correlations between the severity of the arrhythmic events, the cardiac autonomic balance (assessed by heart rate variability analysis in the time domain) and the degree of left ventricular systolic impairment. A population of 14 male healthy individuals served as the control group. BMD subjects exhibited lower values of SDNN (P=0.013), SDANN index (P=0.008) and 24-h mean heart rate (P=0.002). The total number of premature ventricular beats (totPVB) and the number of PVB out of 1000 heartbeats (PVB/1000) appeared also higher in BMD subjects (P=0.05 and P=0.046, respectively). No difference was found in terms of 24-h mean QTc and 24-h longest QT among the two groups. TotPVB and PVB/1000 were inversely related to both the ejection fraction (r= -0.620, P=0.004 and r= -0.517, P=0.019) and to the shortening fraction (r= -0.568, P=0.009 and r= -0.469, P=0.037). Twenty-four-h mean QTc was also inversely related to both the ejection fraction (r= -0.520, P=0.019) and the fractional shortening (r= -0.491, P=0.028). These data suggest that in BMD there is cardiac autonomic imbalance characterized by sympathetic predominance and an increased susceptibility to ventricular arrhythmias, even in the absence of overt cardiomyopathy. Furthermore, the severity of the arrhythmic profile in BMD appears closely related to the degree of left ventricular systolic dysfunction.

Development of cardiomyopathy in female carriers of Duchenne and Becker muscular dystrophies.

OBJECTIVE: To characterize the presence and behavior of the dystrophinopathic myocardial damage in female carriers of a gene defect at the Xp21 locus of the X chromosome that causes Duchenne and Becker muscular dystrophies (DMD and BMD). DESIGN: Cohort study from April 1, 1985, to April 30, 1995, with cardiologic follow-up performed yearly for a minimum of 3 to a maximum of 10 years. SETTING: Counseling center for genetic muscular disorders. PATIENTS: A total of 197 women and girls aged 5 to 60 years ascertained to be carriers of the DMD (n = 152) or BMD (n = 45) gene. MAIN OUTCOME MEASURES: Cardiac status at yearly examinations as determined by 12-lead electrocardiogram (ECG), 24-hour ambulatory ECG, M-mode and 2-dimensional echocardiography, and carotid pulse tracing. Myocardial scintigram was performed on each individual at least twice during the study. Immunohistochemical analysis of dystrophin from myocardium and/or skeletal muscle biopsy was performed in 12 carriers. RESULTS: Preclinical or clinically evident myocardial involvement was found in 166 cases (84.3%), without significant differences in percentage and behavior between DMD and BMD carriers. Its occurrence increased significantly with age, from 54.5% (18 cases) in carriers aged between 5 and 16 years to 90.2% (148 cases) in carriers older than 16 years. Dystrophin anomalies were detected at the membrane level of the myocardial fibers in all endomyocardial biopsy specimens. CONCLUSIONS: Genetic anomalies can be considered the primary cause of myocardial damage in carriers of dystrophinopathic myopathies; myocardial damage shows the same behavior already described in DMD and BMD patients and progresses from preclinical to dilated cardiomyopathy, passing through stages of myocardial hypertrophy or dysrhythmias.

Evaluation of the cardiomyopathy in Becker muscular dystrophy.

To evaluate the features and the course of cardiomyopathy in Becker muscular dystrophy, 68 patients--identified by clinical assessment and by reduced dystrophin labeling and/or DNA analysis--were followed in the years 1976-1993, for periods ranging from 3 to 18 years (mean 8). Patients periodically underwent clinical, electrocardiographic, echocardiographic, nuclear, and radiological assessments. Preclinical cardiac involvement was found in 67.4% of patients under 16 years of age, decreasing to 30% in patients older than 40. Clinically evident cardiomyopathy was found in 15% of patients under 16 years of age, increasing to 73% in patients older than 40. A real, dilated cardiomyopathy is the most frequent type of myocardial involvement after the age of 20. Results show that the severity of cardiac involvement can be unrelated to the severity of skeletal muscle damage and confirm that cardiac dysfunction is a primary feature of Becker muscular dystrophy.

Mutation of dystrophin gene and cardiomyopathy.

The correlations between the type of gene mutation and the cardiac clinical picture were examined in 284 patients with dystrophinopathy (200 Duchenne and 84 Becker). The subjects with normal heart showed deletions including exons 48-49 in 21.4% DMD and in 25% BMD, and other deletions in 35.7% DMD and 25% BMD; vice versa the cases with severe cardiac involvement showed deletions including 48-49 in 38.8% DMD and 37.5% BMD and other deletions in 32.9% DMD and 20% BMD. The age of death was 18 years in DMD patients with deletions including 48-49 whereas the age was about 22 in the cases with other deletions. The differences were statistically significant.

The cardiomyopathy of Duchenne/Becker consultands.

Clinical, electrocardiographic, echocardiographic and other instrumental examinations were performed on 233 persons primarily seeking genetic advice about the Duchenne/Becker gene in order to reveal the incidence of dystrophic cardiomyopathy in a population of females with a close relationship with patients suffering from Duchenne or Becker muscular dystrophy. Among these consultands, 210 were Duchenne and 23 Becker. Eight five (40.4%) Duchenne and 8 (34.8%) Becker consultands showed a normal cardiac status; 35 (16.6%) Duchenne and 6 (26.1%) Becker had clinically evident cardiomyopathy; 90 (43%) Duchenne and 9 (39.1%) Becker showed minor signs of myocardial involvement. The link between myocardial involvement and the Duchenne/Becker carrier condition was demonstrated through the observation that the percentage of cases showing pre-clinical or clinically evident cardiomyopathy was higher in the consultands with pathological values of serum creatine kinase activity (obligatory carriers) and/or an estimated genetic risk higher than 70% than in the consultands showing a normal value of serum creatine kinase activity (less than 80 U/l) and/or a genetic risk lower than 70%.

The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy.

To assess the incidence, nature and evolution of cardiac disease in Duchenne muscular dystrophy, 328 patients were studied between 1976 and 1987 for periods varying from 3 to 11 years. Patients underwent regular clinical examination, electrocardiography, echocardiography and radiological assessment. Pre-clinical cardiac involvement was found in 25% of patients under 6 years old increasing to 59% between the ages of 6 and 10 years and then declining in incidence with age. Clinically apparent cardiomyopathy is first evident after 10 years of age and increases in incidence with age, being present in all patients over 18 years of age. Its clinical impact is discussed.

Prospective study of X-linked progressive muscular dystrophy in Campania.

Within the Campania region of southern Italy a prospective study on X-linked progressive muscular dystrophy was conducted over a period of 12 years from 1969 to 1980, inclusive. The mean incidence rate was 21.7 per 100,000 male livebirths for Duchenne muscular dystrophy (DMD) cases and 3.2 per 100,000 male livebirths for Becker muscular dystrophy (BMD) cases. The familial cases were 38.5% among the DMD patients and 50% among the BMD patients. Myocardial involvement appeared in DMD patients at about 6 years of age in a high percentage of cases and increased progressively until the last years of life, when cardiac damage occurred in 95% of cases. The percentage of myocardial involvement in BMD patients was very low before 13 years of age, but increased progressively until 20 years, when cardiac damage occurred in 80% of cases studied; severe cardiomyopathy did not occur before the age of 21. The data reported also include the effects of age on physical performance, serum creatine kinase activity and serum myoglobin levels, the types of cardiac damage, and the causes of death.