Merosin-deficient congenital muscular dystrophy in Korea

Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of muscle disorders, presenting at birth or early infancy with hypotonia, muscle weakness, joint contractures, and dystrophic changes in the muscles. Merosin-deficient CMD (MDCMD) is rare in Asian populations, but more common in Caucasians, comprising about 50% of CMDs. We report, for the first time in Korea, eight patients with merosin-deficient CMD, confirmed by immunohistochemical staining of muscle or skin samples. We also describe their wide spectrum of clinical features and neuroimaging findings. Among 35 patients diagnosed as CMD, almost 23% of them were proved to have MDCMD with typical phenotypic presentation. We infer that prevalence of MDCMD in Korea may not be as low as expected. One of the patients was diagnosed by skin biopsy, which is good alternative for diagnosis of MDCMD.     

The magnetic resonance imaging spectrum of facioscapulohumeral muscular dystrophy

Introduction: Facioscapulohumeral muscular dystrophy (FSHD) is associated with a repeat contraction in the D4Z4 gene locus on chromosome 4q35. We used a one‐step quantitative magnetic resonance imaging (MRI) method to evaluate muscle, edema, and fat in patients spanning the range of severity. Methods: Fifteen patients with FSHD were compared with 10 healthy subjects using non‐negative linear least‐squares fitting of 32‐echo relaxation data (T2). The results were compared with a biexponential approach for characterizing muscle/fat ratio and T2 relaxation measurements from fat‐suppressed inversion recovery. Results: Increased T2 signal consistent with edema was common in FSHD subjects, a pattern not present in healthy controls. A varied pattern of edema and fatty replacement in muscles was shown. Conclusions: As a discrete biomarker, edema may be useful for following the clinical course of FSHD. Future work toward optimizing measurement is discussed. Muscle Nerve, 2012     

Merosin-deficient congenital muscular dystrophy in an Omani boy

Merosin-deficient congenital muscular dystrophy is an autosomal recessive disease that can manifest differently in different ethnic groups. This often presents as a floppy infant, and normal mental development. The creatine kinase is usually elevated with white matter abnormalities on brain imaging. In this report, we describe an infant with Merosin-deficient congenital muscular dystrophy who presented with delayed motor milestones and hypotonia. The clinical features, biopsy findings, and neuroimaging abnormalities in our patient are described.     

Merosin-negative congenital muscular dystrophy: magnetic resonance spectroscopy findings

Congenital muscular dystrophies (CMD) are heterogeneous group of muscle disorders with autosomal recessive inheritance. Merosin deficiency has been identified in some patients with CMD all of whom also had white matter abnormalities on MRI. In postmortem studies, the brain showed extensive myelin pallor with a spongy appearance of white matter and moderate astrocytosis or demyelination. Direct assessment of neuropathologic aspects of MN-CMD such as demyelination is possible with MR spectroscopy (MRS). Although previous reports have described several neuro-imaging findings of this disease, MRS findings have not been reported in literature. In this case, we report MRS features of a 4-year old girl with MN-CMD. MRS of brain demonstrated that N-acetylaspartate (NAA)/Creatine (Cr) ratio was normal. Increased Choline (Cho)/Cr and Myo-inositol (MI)/Cr ratios were obtained. These findings were interpreted as demyelination and gliosis of white matter.     

Selective muscle involvement on magnetic resonance imaging in autosomal dominant Emery-Dreifuss muscular dystrophy

OBJECTIVE: The aim of this study was to evaluate the spectrum of muscle involvement on MRI in patients with autosomal dominant Emery-Dreifuss muscular dystrophy (EDMD2) due to mutations in the lamin A/C gene and to compare it to the pattern found in other conditions with similar phenotype. PATIENTS AND METHODS: Nine patients with a diagnosis of EDMD2 had MRI scanning of their leg muscles. Seven other patients, four with the X-linked form of Emery-Dreifuss muscular dystrophy (EDMD) and three with an Emery-Dreifuss-like phenotype but no detectable mutations in either the emerin or the lamin A/C gene were also scanned as disease controls. RESULTS: All patients with EDMD2 showed a characteristic involvement of the posterior calf muscles. The medial head of the gastrocnemius was always predominantly involved while the lateral head was relatively spared. This pattern was more obvious in mildly affected patients in whom the other calf muscles were spared or only mildly involved but was also recognisable in the patients with more advanced disease. In contrast, none of the patients with the X-linked EDMD or with Emery-Dreifuss-like phenotype but no mutation in either genes showed this pattern of muscle involvement. CONCLUSIONS: Our results suggest that patients with EDMD2 have a specific pattern of muscle involvement and that muscle MRI can be used, in combination with other techniques, to distinguish various genetic forms of Emery-Dreifuss muscular dystrophy.     

Early white matter changes on brain magnetic resonance imaging in a newborn affected by merosin-deficient congenital muscular dystrophy

In 1996 we reported sequential magnetic resonance imaging study in an infant with merosin-deficient congenital muscular dystrophy with normal brain magnetic resonance imaging at 3 weeks and white matter changes by 6 months. We now report an infant with merosin-deficient congenital muscular dystrophy with a mild degree of white matter changes already present on brain magnetic resonance imaging at 5 days of age. The difference may be due to a difference in the T2 sequences used. The images in this present case were obtained with a fast spin echo sequence (echo time: 210 ms). The increased T2 weighted may be responsible for a better detection of the white matter changes at an early stage, when they can be missed on conventional, less weighting T2 sequences. These results suggest that, by using appropriate sequences, mild white matter changes may be detectable on brain magnetic resonance imaging in the first days of life in infants with merosin-deficient congenital muscular dystrophy.     

High resolution magnetic resonance imaging of the brain in the dy/dy mouse with merosin-deficient congenital muscular dystrophy

Magnetic resonance imaging (MRI) abnormalities in the cerebral white matter are a consistent feature of merosin-deficient human congenital muscular dystrophy, a disease caused by a primary defect in the expression of the laminin alpha2 chain of merosin. To investigate the relationship between imaging changes and merosin deficiency we undertook a MRI study in the dy/dy mouse, an animal model for this form of human congenital muscular dystrophy. High resolution in vivo imaging was performed on anaesthetized animals (two homozygous dy/dy mutants and two heterozygous dy/DY controls, aged 2.5 months) in a dedicated 11.7T magnetic resonance imaging scanner. T(1) and T(2) weighted images were normal in all mice and white matter changes were not seen at a stage of maturity when MRI changes are already very striking in human patients. Cerebral MRI abnormalities do not appear to be a feature of dy/dy mice, despite the virtual absence of merosin expression in the dy/dy mouse brain. Possible causes for this absence of MRI changes, and implications for the pathogenesis of the MRI changes in humans are reviewed.     

Muscle magnetic resonance imaging in patients with congenital muscular dystrophy and Ullrich phenotype

The aim of this study was to evaluate muscle magnetic resonance imaging findings in patients with congenital muscular dystrophy and Ullrich phenotype. Fifteen children with congenital muscular dystrophy and Ullrich phenotype were included in the study. All patients had collagen VI studies in muscle and, when family structure was informative, linkage studies to the collagen 6 loci. Three of the 15 patients had reduced collagen in muscle. One of the three was from an informative family and linked to one of the collagen 6 loci. Another patient was linked to one of the collagen 6 loci but had normal expression of collagen in muscle. The remaining 11 all had normal collagen expression in muscle. Only two of these 11 were from informative families and linkage to collagen 6 loci was excluded in them. All patients had muscle magnetic resonance imaging of their leg muscles using transverse T1 sequences. With the exception of the two patients in whom linkage to the collagen 6 loci was excluded, the other 13 patients showed the same pattern of selective involvement on magnetic resonance imaging of thigh muscles. This consisted of relative sparing of sartorius, gracilis, adductor longus and rectus. This pattern was also found in the case linked COL6A1/A2 locus but with normal collagen. This finding, and the striking clinical and magnetic resonance imaging concordance between patients with normal and reduced collagen VI in muscle suggest that collagen VI could still be the culprit in several cases with normal collagen expression, or alternatively a primary defect in a protein that closely interacts with collagen VI. Mutation analysis of the collagen 6 genes in cases with normal collagen VI expression is needed to resolve this issue.     

Merosin-negative congenital muscular dystrophy: diffusion-weighted imaging findings of brain

Merosin-negative congenital muscular dystrophy is a rare genetic disease of childhood involving the central and peripheral nervous system. There were high signal intensities throughout the centrum semiovale, periventricular, and sub-cortical white matters on T2-weighted images in a 4-year-old girl with merosin-negative congenital muscular dystrophy. An apparent diffusion coefficient map revealed increased signal intensity and apparent diffusion coefficient values in the periventricular and deep white matters. It may be attributable to increased water content in the white matter because of an abnormal blood-brain barrier rather than to decreased or abnormal myelination.     

Merosin-deficient congenital muscular dystrophy associated with abnormal cerebral cortical gyration: an autopsy study

We report clinical, biopsy and autopsy findings in a merosin-deficient congenital muscular dystrophy (CMD) infant with abnormal cortical gyration. Brain showed polymicrogyria and occipital agyria with marginal neuroglial heterotopia and inferior vermis hypoplasia. There was a normal pattern of myelination consistent with early age. Laminin alpha 2 chain was also absent in myocardium, brain pial-glial membrane, brain and skin blood vessels as well as intramuscular and skin nerves. Occasional basal lamina gaps were found in muscle fibres but not in brain-blood vessels. This is the first autopsy study in a merosin-deficient CMD case with abnormal cortical gyration.     

Nonmuscular involvement in merosin-negative congenital muscular dystrophy

The spectrum of nonmuscular involvement in six children with merosin-negative congenital muscular dystrophy is described. In all children, biochemical, neuroradiologic, cardiac, and neurophysiologic studies were performed. Cerebral structures that were myelinated at gestation, including internal capsule, corpus callosum, brainstem, and cerebellar white matter, demonstrated no abnormalities, whereas the periventricular and subcortical white matter, which were myelinated in the first postnatal year, demonstrated signs of leukoencephalopathy. Cerebrospinal fluid analysis revealed an elevated albumin cerebrospinal fluid to serum ratio in the younger children. Electroencephalogram results were abnormal in the two elder children. One child suffered from congestive cardiomyopathy. The increase in nerve conduction velocity in these children over the years lagged behind those of healthy patients, pointing to a demyelinating neuropathy. We conclude that in merosin-negative congenital muscular dystrophy patients, nonmuscular involvement includes the central and peripheral nervous system and the heart. The pattern of myelination of the brain and nerve conduction slowing suggests a myelination arrest. Merosin deficiency can give rise to a congestive cardiomyopathy, which is of no clinical relevance in the majority of children.     

Proton magnetic resonance spectroscopy of brain in congenital myotonic dystrophy

Volume selective proton magnetic resonance spectroscopy of brain was performed on a 1.5 T magnet in 5 patients with congenital muscular dystrophy and compared to the results in 46 healthy children and 1 healthy adult. Peaks of N-acetyl aspartate, choline, and creatine but not lactate, were observed in both groups on proton magnetic resonance spectroscopy. Spectroscopy of controls revealed an increase with advancing age in the ratio of N-acetyl aspartate/choline and N-acetyl aspartate/creatine and a decrease in the choline/creatine ratio. In patients with congenital myotonic dystrophy, the N-acetyl aspartate/choline ratio did not increase with advancing age, but the N-acetyl aspartate/creatine ratio did. The choline/creatine ratio decreased with advancing age, which matched the results of controls. At any age older than 4 years, the N-acetyl aspartate/choline and N-acetyl aspartate/creatine ratios were lower in patients with congenital myotonic dystrophy than in controls. The choline/creatine ratio did not differ between congenital myotonic dystrophy and controls. These results suggest that in patients with congenital myotonic dystrophy N-acetyl aspartate decreases and there exists a developmental disorder of neurons in brain.     

Three-dimensional MR imaging of brain surface anomalies in fukuyama-type congenital muscular dystrophy

Fukuyama-type congental muscular dystrophy (FCMD), the second most common childhood muscular dystrophy in Japan, is characterized by the association with severe brain anomalies such as pachygyria and focal interhemispheric fusion. Conventional imaging techniques such as X-ray CT scan and MRI are ineffective for visualization of these brain surface anomalies. Here we investigated the efficacy of three-dimensional (3-D) reconstruction of brain surface MR images for the detection of brain anomalies in FCMD patients. 3-D brain surface MR images clearly visualized anomalies of cerebral gyrus such as pachygyria, as well as focal interhemispheric fusion. In addition, reconstructed horizontal images visualized structural derangement such as abnormal protrusion of white matter into gray matter. MR image abnormalities were confirmed by autopsy in 1 patient. These abnormalities were never observed in Duchenne muscular dystrophy (DMD) patients. Our results indicate the efficacy of the present method for the differential diagnosis between FCMD and DMD with severe mental retardation, which is essential for the genetic study to identify the causative gene of FCMD. © 1995 John Wiley & Sons, Inc.     

Cardiovascular magnetic resonance imaging evaluation of two families with Becker muscular dystrophy

In this study we evaluated two families with Becker muscular dystrophy and although the patients were completely asymptomatic and with normal ECG and echocardiogram, their left ventricular function was abnormal and the presence of subepicardial scar tissue was identified in the majority of them. The latter was also documented in one of the mothers, who had normal systolic function and was free of symptoms. Cardiac evaluation with cardiovascular magnetic resonance is sensitive enough to detect abnormal findings in BMD patients, missed by conventional echocardiography. Due to its ability to perform tissue characterization non-invasively, cardiovascular magnetic resonance can detect silent myocardial lesions in patients with Becker muscular dystrophy.     

Whole‐body magnetic resonance imaging evaluation of facioscapulohumeral muscular dystrophy

Introduction: Facioscapulohumeral muscular dystrophy (FSHD) is a hereditary disorder that causes progressive muscle wasting. Increasing knowledge of the pathophysiology of FSHD has stimulated interest in developing biomarkers of disease severity. Methods: Two groups of MRI scans were analyzed: whole‐body scans from 13 subjects with FSHD; and upper and lower extremity scans from 34 subjects with FSHD who participated in the MYO‐029 clinical trial. Muscles were scored for fat infiltration and edema‐like changes. Fat infiltration scores were compared with muscle strength and function. Results: The analysis revealed a distinctive pattern of both frequent muscle involvement and frequent sparing in FSHD. Averaged fat infiltration scores for muscle groups in the legs correlated with quantitative muscle strength and 10‐meter walk times. Conclusions: Advances in MRI technology allow for acquisition of rapid, high‐quality, whole‐body imaging in diffuse muscle disease. This technique offers a promising disease biomarker in FSHD and other muscle diseases. Muscle Nerve 52: 512–520, 2015     

Muscle magnetic resonance imaging in patients with LAMA2-related muscular dystrophy

LAMA2-related muscular dystrophy (LAMA2-MD) is classified into congenital muscular dystrophy type 1A (MDC1A) and autosomal recessive limb-girdle muscular dystrophy-23 (LGMDR23). The purpose of this study was to identify the involvement pattern of thigh muscles of LAMA2-MD patients on magnetic resonance imaging. Fourteen MDC1A and 3 LGMDR23 patients were included, with 21 known and 8 novel LAMA2 disease-causing variants. In LAMA2-MD, the gluteus maximus, anterior (quadriceps femoris) and posterior (adductor magnus and biceps femoris) thigh muscles were extensively and severely affected with fatty infiltration, with relatively sparing of the adductor longus. The pattern of muscle involvement was similar between MDC1A and LGMDR23, but more severe in MDC1A, as well as in LAMA2-MD patients without ambulation. The rather peculiar pattern of the adductor magnus and long head of the biceps femoris first and severely affected in the mid-thigh level was found in LGMDR23. Strong correlation between fatty infiltration and age as well as disease duration was observed for the adductor longus in MDC1A. Edema and atrophy selectively involved in some muscles. The pattern of fatty infiltration on thigh muscle MRI of LAMA2-MD could provide important information for the diagnosis, differential diagnosis and assessment of clinical severity.     

Quantitative magnetic resonance imaging of the mdx mouse model of Duchenne muscular dystrophy.

The mdx mouse has a genetically homologous disease to Duchenne muscular dystrophy in humans. The disease progression, however, is not accompanied by the same level of fatty infiltration and muscle degeneration as occurs in humans. Thus, the presence of histological/pathological changes in living mdx mice has been difficult to monitor. We quantified proton density and the T2 relaxation time of protons with a resolution of 195 x 195 x 1000 microm using multiecho magnetic resonance (MR) imaging at 7 Tesla. These relaxation data were correlated with water content in both muscle and brain of mdx and controls. No differences were observed in brain. The mdx muscles had increased water content and proton density and decreased T2 relative to controls. These data indicate that there are intrinsic changes in T2 (opposite to that which would be induced by fatty infiltration) and suggest that T2 imaging could be used to monitor progression and treatment in this animal model.     

Magnetic resonance imaging phenotyping of Becker muscular dystrophy

Introduction: There is little information on magnetic resonance imaging (MRI) phenotypes of Becker muscular dystrophy (BMD). This study presents the MRI phenotyping of the upper and lower extremities of a large cohort of BMD patients. Methods: In this retrospective study, MRI images of 33 BMD subjects were evaluated for severity, distribution, and symmetry of involvement. Results: Teres major, triceps long head, biceps brachii long head, gluteus maximus, gluteus medius, vasti, adductor longus, adductor magnus, semitendinosus, semimembranosus, and biceps femoris muscles showed the highest severity and frequency of involvement. All analyzed muscles had a high frequency of symmetric involvement. There was significant variability of involvement between muscles within some muscle groups, most notably the arm abductors, posterior arm muscles, medial thigh muscles, and lateral hip rotators. Conclusions: This study showed a distinctive pattern of involvement of extremity muscles in BMD subjects. Muscle Nerve 50: 962–967, 2014