Umbertina Conti Reed

Congenital muscular dystrophy. Part I: a review of phenotypical and diagnostic aspects

The congenital muscular dystrophies (CMDs) are a group of genetically and clinically heterogeneous hereditary myopathies with preferentially autosomal recessive inheritance, that are characterized by congenital hypotonia, delayed motor development and early onset of progressive muscle weakness associated with dystrophic pattern on muscle biopsy. The clinical course is broadly variable and can comprise the involvement of the brain and eyes. From 1994, a great development in the knowledge of the molecular basis has occurred and the classification of CMDs has to be continuously up dated. We initially present the main clinical and diagnostic data concerning the CMDs related to changes in the complex dystrophin-associated glycoproteins-extracellular matrix: CMD with merosin deficiency (CMD1A), collagen VI related CMDs (Ullrich CMD and Bethlem myopathy), CMDs with abnormal glycosylation of alpha-dystroglycan (Fukuyama CMD, Muscle-eye-brain disease, Walker-Warburg syndrome, CMD1C, CMD1D), and the much rarer CMD with integrin deficiency. Finally, we present other forms of CMDs not related with the dystrophin/glycoproteins/extracellular matrix complex (rigid spine syndrome, CMD1B, CMD with lamin A/C deficiency), and some apparently specific clinical forms not yet associated with a known molecular mechanism. The second part of this review concerning the pathogenesis and therapeutic perspectives of the different subtypes of CMD will be described in a next number.

Nebulin expression in patients with nemaline myopathy

Nemaline myopathy is a structural congenital myopathy which may show both autosomal dominant and autosomal recessive inheritance patterns. Mutations in three different genes have been identified as the cause of nemaline myopathy: the gene for slow alpha-tropomyosin 3 (TPM3) at 1q22-23, the nebulin gene (NEB) at 2q21.1-q22, and the actin gene (ACTA1) at 1q42. The typical autosomal recessive form appears to be the most common one and is caused by mutations in the nebulin gene. We have studied the pattern of nebulin labeling, in patients with the typical congenital form (ten patients), the severe congenital form (two patients) or the mild, childhood-onset form (one patient), using antibodies against three different domains of nebulin. A qualitative and quantitative nebulin analysis in muscle tissue showed the presence of nebulin in myofibers from all patients. Some differences relating to the rod structure were observed. The majority of the largest subsarcolemmal rods were not labeled with the N2 nebulin antibody (I-band epitope) and showed an indistinct pattern with the two antibodies directed to the Z-band portion of nebulin (epitopes M176-181 and serine-rich domain). Diffuse rods were not revealed using the three antibodies. A discordant pattern of nebulin N2 epitope labeling was found in two affected sisters with a mutation in the nebulin gene, suggesting that modifications in nebulin distribution inside the rods might occur with the progression of the disease. Western blot analysis showed no direct correlation with immunofluorescence data. In nine patients, the band had a molecular weight comparable to the normal control, while in one patient, it was detected with a higher molecular weight. Our results suggest that presence/absence of specific nebulin Z-band epitopes in rod structures is variable and could depend on the degree of rod organization.

Sleep and neuromuscular disorders in children

Children suffering from neuromuscular diseases are at an increased risk of sleep-related breathing disorders (SRBD) such as obstructive sleep apnea syndrome (OSAS) and hypoventilation as well as central sleep apnea, which is frequent in these patients due to diaphragmatic weakness. They are at higher risk for developing complications of nocturnal hypoxemia, including pulmonary hypertension, cor pulmonale and neurocognitive dysfunction. Neuromuscular disorders and OSAS are both prevalent disorders and frequently overlap. Sleep-related hypoventilation/hypoxemia due to neuromuscular diseases may be exacerbated in the presence of OSAS; these children are likely to experience greater severity and duration of sleep-related hypoxemia than are children with either disorder alone. Additionally, some of these children have reduced central neural chemoresponsiveness. The development of SRBD in these patients further impairs their quality of life and worsens their respiratory status. We review the literature on the diagnosis and treatment of SRBD in children with a variety of neuromuscular disorders.

Congenital muscular dystrophy. Part II: a review of pathogenesis and therapeutic perspectives

The congenital muscular dystrophies (CMDs) are a group of genetically and clinically heterogeneous hereditary myopathies with preferentially autosomal recessive inheritance, that are characterized by congenital hypotonia, delayed motor development and early onset of progressive muscle weakness associated with dystrophic pattern on muscle biopsy. The clinical course is broadly variable and can comprise the involvement of the brain and eyes. From 1994, a great development in the knowledge of the molecular basis has occurred and the classification of CMDs has to be continuously up dated. In the last number of this journal, we presented the main clinical and diagnostic data concerning the different subtypes of CMD. In this second part of the review, we analyse the main reports from the literature concerning the pathogenesis and the therapeutic perspectives of the most common subtypes of CMD: MDC1A with merosin deficiency, collagen VI related CMDs (Ullrich and Bethlem), CMDs with abnormal glycosylation of alpha-dystroglycan (Fukuyama CMD, Muscle-eye-brain disease, Walker Warburg syndrome, MDC1C, MDC1D), and rigid spine syndrome, another much rare subtype of CMDs not related with the dystrophin/glycoproteins/extracellular matrix complex.

Merosin-deficient congenital muscular dystrophy (CMD) : a study of 25 Brazilian patients using MRI

Background: Merosin-deficient congenital muscular dystrophy (CMD) is characterized clinically by hypotonia and muscular weakness and, on imaging studies, by white matter (WM) abnormality. Objective: To evaluate MRI findings in Brazilian patients with merosin-deficient CMD. Materials and methods: Twenty-five patients were evaluated using MRI. Three patients presented with partial merosin deficiency and 22 with total merosin deficiency. Follow-up examinations were done in 7 cases. T1- and T2-weighted images were performed in all examinations, and fluid-attenuated inversion recovery (FLAIR) was performed in 15. Enhanced images were done in 11 cases. The WM involvement was classified according to location and severity. Results: From 1991 to 2004, 32 MRI examinations were performed. Severe involvement was found in 23 patients in the frontal and temporal lobes, in 18 patients in the parietal lobes, and in 7 patients in the occipital lobes. The brain stem (n=5), cerebellum (n=6), internal capsules (n=1), and external capsules (n=5) were also affected. One patient had occipital pachygyria, and one had cerebellar vermian hypoplasia. No gadolinium enhancement was noted. Follow-up MRI showed no interval change (n=4), progression (n=1), or improvement of the findings (n=2). Conclusion: This series of patients demonstrated that there was no correlation between the extent of WM abnormality on MRI and the clinical status and degree of merosin deficiency (partial or total). Bilateral WM involvement was seen to be more prominent in the parietal, frontal, and temporal regions of the brain. The brain stem and internal and external capsules were less affected. Cerebellar WM involvement is rare. Changes on follow-up imaging studies did not correlate with the clinical status of the patient.

Comparison of motor strength and function in patients with Duchenne muscular dystrophy with or without steroid therapy

OBJECTIVE To compare muscle strength (MS) and motor function in patients with Duchenne muscular dystrophy (DMD) receiving steroids for different times against the natural evolution of DMD described by Scott et al. METHOD 90 patients with DMD (aged 5- 12 years), receiving steroids for one to seven years, were evaluated by Medical Research Council Scale (MRC) and Hammersmith motor ability score. The relation between MS and motor abilities measurement from our data and Scotts ones were ascertained statistically. RESULTS The relation between patients age and Hammersmith scores revealed decrease of 0.76 point per year for age against decrease of 2.23 points on Scotts study. The relation between MRC scale and patients age showed decrease of 0.80 point per year of age against decrease of 3.65 points on Scotts study. CONCLUSION In patients with DMD aged five to 12 years the progression of the disease is delayed by steroids and the motor function is less reduced than muscular strength.

Quantification of muscle strength and motor ability in patients with Duchenne muscular dystrophy on steroid therapy

OBJECTIVE An assessment protocol was applied to quantify and describe muscular strength and motor abilities of 32 patients with Duchenne muscular dystrophy (DMD), aged between 5 and 12 years on steroid therapy. METHOD Assessments were made monthly for the first six months and with intervals of two months thereafter until the 14-month end point. The tests employed included: the Medical Research Council (MRC) scale; the Hammersmith motor ability score; maximum weight lift; timed rise from floor and nine-meter walk. RESULTS The results showed that loss of muscular strength and motor abilities were slowed in comparison to that observed in the natural evolution of the disease according to the literature. CONCLUSION We conclude that a swift and objective assessment may be performed using the MRC scale for lower limbs and trunk, the Hammersmith motor ability score, timed nine-meter walk and weight lifts.

Evaluation of muscle strength and motor abilities in children with type II and III spinal muscle atrophy treated with valproic acid.

BackgroundSpinal muscular atrophy (SMA) is an autosomal recessive disorder that affects the motoneurons of the spinal anterior horn, resulting in hypotonia and muscle weakness. The disease is caused by deletion or mutation in the telomeric copy of SMN gene (SMN1) and clinical severity is in part determined by the copy number of the centromeric copy of the SMN gene (SMN2). The SMN2 mRNA lacks exon 7, resulting in a production of lower amounts of the full-length SMN protein. Knowledge of the molecular mechanism of diseases has led to the discovery of drugs capable of increasing SMN protein level through activation of SMN2 gene. One of these drugs is the valproic acid (VPA), a histone deacetylase inhibitor.MethodsTwenty-two patients with type II and III SMA, aged between 2 and 18 years, were treated with VPA and were evaluated five times during a one-year period using the Manual Muscle Test (Medical Research Council scale-MRC), the Hammersmith Functional Motor Scale (HFMS), and the Barthel Index.ResultsAfter 12 months of therapy, the patients did not gain muscle strength. The group of children with SMA type II presented a significant gain in HFMS scores during the treatment. This improvement was not observed in the group of type III patients. The analysis of the HFMS scores during the treatment period in the groups of patients younger and older than 6 years of age did not show any significant result. There was an improvement of the daily activities at the end of the VPA treatment period.ConclusionTreatment of SMA patients with VPA may be a potential alternative to alleviate the progression of the disease.Trial RegistrationClinicalTrials.gov: NCT01033331

Reaction time assessment in children with ADHD

UNLABELLED Attention deficit, impulsivity and hyperactivity are the cardinal features of attention deficit hyperactivity disorder (ADHD) but executive function (EF) disorders, as problems with inhibitory control, working memory and reaction time, besides others EFs, may underlie many of the disturbs associated with the disorder. OBJECTIVE To examine the reaction time in a computerized test in children with ADHD and normal controls. METHOD Twenty-three boys (aged 9 to 12) with ADHD diagnosis according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, 2000 (DSM-IV) criteria clinical, without comorbidities, Intelligence Quotient (IQ) > or = 89, never treated with stimulant and fifteen normal controls, age matched were investigated during performance on a voluntary attention psychophysical test. RESULTS Children with ADHD showed reaction time higher than normal controls. CONCLUSION A slower reaction time occurred in our patients with ADHD. This findings may be related to problems with the attentional system, that could not maintain an adequate capacity of perceptual input processes and/or in motor output processes, to respond consistently during continuous or repetitive activity.

Impact of benign childhood epilepsy with centrotemporal spikes (BECTS) on school performance

UNLABELLED BECTS represents the vast majority of childhood focal epilepsy. Owing to the age peculiarity of children who suffer from this disease, i.e., school-going age of between 6 and 9 years, the condition is often referred to as a school disorder by parents and teachers. OBJECTIVE The aim of this study was to evaluate the academic performance of children with BECTS, according to the clinical and electroencephalographic ILAE criteria, and compare the results of neuropsychological tests of language and attention to the frequency of epileptic discharges. METHODS The performances of 40 school children with BECTS were evaluated by applying a school performance test (SBT), neuropsychological tests (WISC and Trail-Making), and language tests (Illinois Test Psycholinguistic Abilities-ITPA--and Staggered Spondaic Word-SSW). The same tests were applied in the control group. RESULTS Children with BECTS, when compared to those in the control group, showed lower scores in academic performance (SPT), digits and similarities subtests of WISC, auditory processing subtest of SSW, and ITPA--representational and automatic level. The study showed that epileptic discharges did not influence the results. CONCLUSION Children with BECTS scored significantly lower scores in tests on academic performance, when compared with those in the control group probably due to executive dysfunction.