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Background and ObjectivesThe goal of this work was to determine whether locally acting ACE-083 is safe and well tolerated and increases muscle volume, motor function, and quality of life (QoL) in adults with Charcot-Marie-Tooth disease (CMT) type 1.MethodsThis phase 2 study enrolled adults with CMT1 or CMTX (N = 63). Part 1 was open label and evaluated the safety and tolerability of different dose levels of ACE-083 for use in part 2. Part 2 was a randomized, placebo-controlled, 6-month study of 240 mg/muscle ACE-083 injected bilaterally into the tibialis anterior muscle, followed by a 6-month, open-label extension in which all patients received ACE-083. Pharmacodynamic endpoints included total muscle volume (TMV; primary endpoint), contractile muscle volume (CMV), and fat fraction. Additional secondary endpoints included 6-minute walk test, 10-m walk/run, muscle strength, and QoL. Safety was assessed with treatment-emergent adverse events (TEAEs) and clinical laboratory tests.ResultsIn part 1 (n = 18), ACE-083 was generally safe and well tolerated at all dose levels, with no serious adverse events, TEAEs of grade 3 or greater, or death reported. In part 2 (n = 45 enrolled, n = 44 treated), there was significantly greater change in TMV with ACE-083 compared with placebo (least-squares mean difference 13.5%;p= 0.0096). There was significant difference between ACE-083 and placebo for CMV and change in ankle dorsiflexion strength. Fat fraction and all other functional outcomes were not significantly improved by ACE-083. Moderate to mild injection-site reactions were the most common TEAEs.DiscussionDespite significantly increased TMV and CMV, patients with CMT receiving ACE-083 in tibialis anterior muscles did not demonstrate greater functional improvement compared with those receiving placebo.Trial Registration InformationClinical Trials Registration:NCT03124459.Classification of EvidenceThis study provides Class II evidence that intramuscular ACE-083 is safe and well tolerated and increases total muscle volume after 6 months of treatment in adults with CMT1 or CMTX.

ObjectiveTo describe the features of a new, pathologically distinctive, acquired myopathy with an unusual pattern of scattered necrotic muscle fibers that are neighbored, surrounded, or invaded, by large, often multinucleated, histiocytic cells.MethodsRetrospective review of records and muscle pathology of 4 patients.ResultsClinical features common to our patients included muscle pain and proximal, symmetric, moderate to severe, weakness in the arms and legs progressing over 1–4 weeks. Patients had other associated systemic disorders, including anemia in all, and hemophagocytic lymphohistiocytosis, hepatic disease, Raynaud phenomenon, metastatic cancer, and cardiomyopathy, in 1 patient each. Serum creatine kinase (CK) levels at presentation were very high, ranging from 10,000 to 102,000 U/L. Three patients improved within 3 months after treatment. Muscle pathology included scattered necrotic muscle fibers with cytoplasm that stained for C5b-9 complement, especially around fiber peripheries, pale on nicotinamide adenine dinucleotide and often dark on hematoxylin & eosin. Large, often multinucleated, cells with features of histiocytes, including anatomical features on electron microscopy and immunostaining for major histocompatibility complex Class I and histiocyte markers (HAM56, CD68, CD163, and S100), were usually closely apposed to the surface of, or invaded, necrotic myofibers.ConclusionsPatients with large-histiocyte-associated myopathy (LHIM) had a subacute onset of proximal predominant weakness, associated systemic disorders, very high serum CK, and a pathologically distinctive pattern of large histiocyte-associated muscle fiber necrosis. LHIM may be caused by an autoimmune, histiocyte-mediated attack directed against muscle fibers.

Objective To assess the intraepidermal nerve fiber density in patients diagnosed with fibromyalgia (FM) and to evaluate the role of IgM binding to trisulfated heparin disaccharide (TS-HDS) in these patients. Methods FM is a poorly understood pain disorder with several proposed pathophysiologic mechanisms. It is characterized by widespread pain, fatigue, and sleep abnormalities. Small fiber neuropathy (SFN) has been proposed as an underlying mechanism, and patients with FM have been shown to have a reduction in the intraepidermal nerve fiber density. An underlying inflammatory process that could be a result of autoimmune phenomena has also been suggested. Non-length-dependent SFN (NLDSFN) has been shown to have a higher incidence of autoimmune disease. Twenty-two patients with established diagnosis of FM underwent skin biopsy at 2 sites; 10 cm above the lateral malleolus and 10 cm above the patella. Serum IgM binding to TS-HDS was assayed using an ELISA method. Results A total of 5/22 patients had positive TS-HDS antibodies; of these, 4 had NLDSFN (P = 0.0393). Comparison with a control group at Washington University showed no significant difference in percentage with TS-HDS antibodies (P = 0.41). When compared with Washington University database of skin biopsy, there was a trend for an increased percentage of NLDSFN in patients with FM (P = 0.06). Conclusions This study further supports the hypothesis that a subgroup of patients with FM has SFN. We suggest a correlation between the presence of NLDSFN and TS-HDS antibodies.

ObjectiveTo evaluate the relationship between deficit in digit span and genotype in nonsense mutation (nm) Duchenne muscular dystrophy (DMD) (nmDMD).MethodsWe investigated the relationship between normalized digit-span forward (d-sf) and digit-span backward (d-sb) scores to the location of nmDMD mutations in 169 participants ≥5 to ≤20 years who participated in a phase 2b clinical trial. Because alternative promoters are found upstream of DMD exons 30, 45, and 63, we correlated d-sf and d-sb to the specific nmDMD mutation location.ResultsParticipants with nm downstream of exon 30, downstream of exon 45, and downstream of exon 63 had significantly lower normalized d-sf scores (p < 0.0001). Participants with nm downstream of exon 45 in addition had significantly lower normalized d-sb score (p < 0.04). There was no significant difference in the normalized d-sb score in participants with mutations upstream or downstream of DMD exon 30 or upstream or downstream of DMD exon 63.ConclusionOur data provide evidence that specific cognitive deficits correlate to genotype in individuals with nmDMD, highlighting the critical role of brain-specific dystrophin isoforms in the neurobiological manifestations of this disease.Clinicaltrials.gov identifierNCT02090959.

Objective: To assess safety and efficacy of deflazacort (DFZ) and prednisone (PRED) vs placebo in Duchenne muscular dystrophy (DMD). Methods: This phase III, double-blind, randomized, placebo-controlled, multicenter study evaluated muscle strength among 196 boys aged 5–15 years with DMD during a 52-week period. In phase 1, participants were randomly assigned to receive treatment with DFZ 0.9 mg/kg/d, DFZ 1.2 mg/kg/d, PRED 0.75 mg/kg/d, or placebo for 12 weeks. In phase 2, placebo participants were randomly assigned to 1 of the 3 active treatment groups. Participants originally assigned to an active treatment continued that treatment for an additional 40 weeks. The primary efficacy endpoint was average change in muscle strength from baseline to week 12 compared with placebo. The study was completed in 1995. Results: All treatment groups (DFZ 0.9 mg/kg/d, DFZ 1.2 mg/kg/d, and PRED 0.75 mg/kg/d) demonstrated significant improvement in muscle strength compared with placebo at 12 weeks. Participants taking PRED had significantly more weight gain than placebo or both doses of DFZ at 12 weeks; at 52 weeks, participants taking PRED had significantly more weight gain than both DFZ doses. The most frequent adverse events in all 3 active treatment arms were Cushingoid appearance, erythema, hirsutism, increased weight, headache, and nasopharyngitis. Conclusions: After 12 weeks of treatment, PRED and both doses of DFZ improved muscle strength compared with placebo. Deflazacort was associated with less weight gain than PRED. Classification of evidence: This study provides Class I evidence that for boys with DMD, daily use of either DFZ and PRED is effective in preserving muscle strength over a 12-week period.

To determine the safety and tolerability of mexiletine in a phase II double-blind randomized controlled trial of sporadic amyotrophic lateral sclerosis (SALS).Sixty participants with SALS from 10 centers were randomized 1:1:1 to placebo, mexiletine 300 mg/d, or mexiletine 900 mg/d and followed for 12 weeks. The primary endpoints were safety and tolerability. Secondary endpoints were pharmacokinetic study from plasma and CSF, ALS Functional Rating Scale-Revised (ALSFRS-R) score, slow vital capacity (SVC), and muscle cramp frequency and severity.The only serious adverse event among active arm participants was one episode of imbalance. Thirty-two percent of participants receiving 900 mg of mexiletine discontinued study drug vs 5% on placebo (p = 0.026). Pharmacokinetic study demonstrated a peak plasma concentration 2 hours postdose and strong correlation between plasma and CSF (p0.001). Rates of decline of ALSFRS-R and SVC did not differ from placebo. Analysis of all randomized patients demonstrated significant reductions of muscle cramp frequency (300 mg: rate = 31% of placebo, p = 0.047; 900 mg: 16% of placebo, p = 0.002) and cramp intensity (300 mg: mean = 45% of placebo, p = 0.08; 900 mg: 25% of placebo, p = 0.005).Mexiletine was safe at both doses and well-tolerated at 300 mg/d but adverse effects at 900 mg/d led to a high rate of discontinuation. Mexiletine treatment resulted in large dose-dependent reductions in muscle cramp frequency and severity. No effect on rate of progression was detected, but clinically important differences could not be excluded in this small and short-duration study.This study provides Class I evidence that mexiletine is safe when given daily to patients with amyotrophic lateral sclerosis at 300 and 900 mg and well-tolerated at the lower dose.

Objective: To identify the genetic etiology and characterize the clinicopathologic features of a novel distal myopathy. Methods: We performed whole-exome sequencing on a family with an autosomal dominant distal myopathy and targeted exome sequencing in 1 patient with sporadic distal myopathy, both with rimmed vacuolar pathology. We also evaluated the pathogenicity of identified mutations using immunohistochemistry, Western blot analysis, and expression studies. Results: Sequencing identified a likely pathogenic c.1165+1 G>A splice donor variant in SQSTM1 in the affected members of 1 family and in an unrelated patient with sporadic distal myopathy. Affected patients had late-onset distal lower extremity weakness, myopathic features on EMG, and muscle pathology demonstrating rimmed vacuoles with both TAR DNA-binding protein 43 and SQSTM1 inclusions. The c.1165+1 G>A SQSTM1 variant results in the expression of 2 alternatively spliced SQSTM1 proteins: 1 lacking the C-terminal PEST2 domain and another lacking the C-terminal ubiquitin-associated (UBA) domain, both of which have distinct patterns of cellular and skeletal muscle localization. Conclusions: SQSTM1 is an autophagic adaptor that shuttles aggregated and ubiquitinated proteins to the autophagosome for degradation via its C-terminal UBA domain. Similar to mutations in VCP, dominantly inherited mutations in SQSTM1 are now associated with rimmed vacuolar myopathy, Paget disease of bone, amyotrophic lateral sclerosis, and frontotemporal dementia. Our data further suggest a pathogenic connection between the disparate phenotypes.

The American population weighs too much. That is so well documented; it does not even need a citation. And for all the millions of pages of research and gray literature devoted to the topic and all the complex reasons for American obesity, we know that Americans tend to eat too much, and too much of the wrong things, while not exercising nearly enough. With the girth of America growing, taking off fatty pounds and, more importantly, keeping them off will go a long way toward mitigating personal and family health catastrophes and future health care costs. Our propensityforexcessweightis,tobesure,relatedtodecisions by individuals. But these decisions are shaped and guided by what we encounter in the places where we work, learn, and play. A new environment around each of us, one less blessed with empty calories and more encouraging to movement and activity, will become us. In the past few years, policy attempts to influence the inputs have been highly visible, from the recent success in reducing sodium in processed foods to the Affordable Care Act’s requirement to place calories on menu boards and the 2010 Healthy Hunger-Free Kids Act, which promoted healthier meals in schools and in childcare centers. While the output side of the equation has not been ignored in research or in our culture, the role of policy in affecting physical activity is nowhere near as visible as the policy focus on nutrition. This issue of the Journal of Public Health Management and Practice is a welcome examination of policy’s role in altering the output side of the equation.

Objective: To compare accuracy of ultrasound and MRI for detecting focal peripheral nerve pathology, excluding idiopathic carpal or cubital tunnel syndromes. Methods: We performed a retrospective review of patients referred for neuromuscular ultrasound to identify patients who had ultrasound and MRI of the same limb for suspected brachial plexopathy or mononeuropathies, excluding carpal/cubital tunnel syndromes. Ultrasound and MRI results were compared to diagnoses determined by surgical or, if not performed, clinical/electrodiagnostic evaluation. Results: We identified 53 patients who had both ultrasound and MRI of whom 46 (87%) had nerve pathology diagnosed by surgical (n = 39) or clinical/electrodiagnostic (n = 14) evaluation. Ultrasound detected the diagnosed nerve pathology (true positive) more often than MRI (43/46 vs 31/46, p 2 cm) and only occasionally (2/13) outside the MRI field of view. MRI missed multifocal pathology identified with ultrasound in 6 of 7 patients, often (5/7) because pathology was outside the MRI field of view. Conclusions: Imaging frequently detects peripheral nerve pathology and contributes to the differential diagnosis in patients with mononeuropathies and brachial plexopathies. Ultrasound is more sensitive than MRI (93% vs 67%), has equivalent specificity (86%), and better identifies multifocal lesions than MRI. In sonographically accessible regions ultrasound is the preferred initial imaging modality for anatomic evaluation of suspected peripheral nervous system lesions.

Objective: To use a historical placebo control design to determine whether lithium carbonate slows progression of amyotrophic lateral sclerosis (ALS). Methods: A phase II trial was conducted at 10 sites in the Western ALS Study Group using similar dosages (300–450 mg/day), target blood levels (0.3–0.8 mEq/L), outcome measures, and trial duration (13 months) as the positive trial. However, taking riluzole was not a requirement for study entry. Placebo outcomes in patients matched for baseline features from a large database of recent clinical trials, showing stable rates of decline over the past 9 years, were used as historical controls. Results: The mean rate of decline of the ALS Functional Rating Scale–Revised was greater in 107 patients taking lithium carbonate (−1.20/month, 95% confidence interval [CI] −1.41 to −0.98) than that in 249 control patients (−1.01/month, 95% CI −1.11 to −0.92, p = 0.04). There were no differences in secondary outcome measures (forced vital capacity, time to failure, and quality of life), but there were more adverse events in the treated group. Conclusions: The lack of therapeutic benefit and safety concerns, taken together with similar results from 2 other recent trials, weighs against the use of lithium carbonate in patients with ALS. The absence of drift over time and the availability of a large database of patients for selecting a matched historical control group suggest that use of historical controls may result in more efficient phase II trials for screening putative ALS therapeutic agents. Classification of evidence: This study provided Class IV evidence that lithium carbonate does not slow the rate of decline of function in patients with ALS over 13 months.

Acquired immune and inflammatory myopathies (IIMs) are typically subdivided into dermatomyositis, polymyositis and inclusion body myositis. However, many types of IIMs do not fit well into this scheme. Several myopathologic and autoantibody features of IIMs, that are not considered in standard classifications, are useful for defining individual disorders. We will review one set of myopathologic features that occur in some IIMs, mitochondrial abnormalities, and consider its diagnostic, treatment-related and pathogenic implications.Myopathologic changes that indicate mitochondrial disorders are often widespread in regions of muscle fiber abnormality in dermatomyositis. They distinguish dermatomyositis with vascular pathology from other inflammatory myopathies with skin changes that have prominent perimysial connective tissue lesions, but no mitochondrial, abnormalities. Mitochondrial abnormalities in scattered muscle fibers occur in sporadic inclusion body myositis and clinically similar disorders. Mitochondrial abnormalities in scattered nonnecrotic muscle fibers in IIM biopsies predict a poor response to immunosuppression.Muscle biopsy, including evaluation of mitochondrial stains, is important for the correct diagnosis of inflammatory myopathies. By recognizing the full range of distinctive myopathologic changes in the diverse group of IIMs, the clinician can improve diagnostic accuracy and apply appropriate treatment.

The relevance of proteins that accumulate and aggregate in the muscle fibers of patients with sporadic inclusion body myositis (sIBM) is unknown. Many of these proteins also aggregate in other disorders, including Alzheimer's disease, leading to speculation that sIBM pathogenesis has similarities to neurodegenerative disorders. Our review will discuss current studies on these protein biomarkers and their utility in sIBM diagnosis.Two 'classical' components of sIBM aggregates (amyloid beta and phospho-tau) have been re-evaluated. Three additional components of aggregates (TDP-43, p62, and LC3) have been identified. The sensitivity and specificity of these biomarkers has been explored. Two studies suggest that TDP-43 may have clinical utility in distinguishing sIBM from other inflammatory myopathies.The fact that sIBM muscle accumulates multiple protein aggregates with no single protein appearing in every sIBM patient biopsy suggests that it is not presently possible to place pathogenic blame on any single protein (i.e. amyloid beta or TDP-43). Instead changes in protein homeostasis may lead to the accumulation of different proteins that have a propensity to aggregate in skeletal muscle. Therapies aimed at improving protein homeostasis, instead of targeting a specific protein that may or may not accumulate in all sIBM patients, could be useful future strategies for this devastating and enigmatic disorder.

Objective: Spinal muscular atrophies (SMAs) are hereditary disorders characterized by weakness from degeneration of spinal motor neurons. Although most SMA cases with proximal weakness are recessively inherited, rare families with dominant inheritance have been reported. We aimed to clinically, pathologically, and genetically characterize a large North American family with an autosomal dominant proximal SMA. Methods: Affected family members underwent clinical and electrophysiologic evaluation. Twenty family members were genotyped on high-density genome-wide SNP arrays and linkage analysis was performed. Results: Ten affected individuals (ages 7–58 years) showed prominent quadriceps atrophy, moderate to severe weakness of quadriceps and hip abductors, and milder degrees of weakness in other leg muscles. Upper extremity strength and sensation was normal. Leg weakness was evident from early childhood and was static or very slowly progressive. Electrophysiology and muscle biopsies were consistent with chronic denervation. SNP-based linkage analysis showed a maximum 2-point lod score of 5.10 (θ = 0.00) at rs17679127 on 14q32. A disease-associated haplotype spanning from 114 cM to the 14q telomere was identified. A single recombination narrowed the minimal genomic interval to Chr14: 100,220,765–106,368,585. No segregating copy number variations were found within the disease interval. Conclusions: We describe a family with an early onset, autosomal dominant, proximal SMA with a distinctive phenotype: symptoms are limited to the legs and there is notable selectivity for the quadriceps. We demonstrate linkage to a 6.1-Mb interval on 14q32 and propose calling this disorder spinal muscular atrophy–lower extremity, dominant.

ObjectiveImmune myopathies with perimysial pathology (IMPP) have a combination of damage to perimysial connective tissue and muscle fiber necrosis, more prominent near the perimysium. We studied the clinical and laboratory correlates of patients with pathologically defined IMPP.MethodsThis is a retrospective chart and pathology review of 57 consecutive patients with IMPP myopathology and, for comparison, 20 patients with dermatomyositis with vascular pathology (DM-VP).ResultsCompared with DM-VP, IMPP patients more commonly had interstitial lung disease (ILD) (p < 0.01), Raynaud phenomenon (p < 0.05), mechanic's hands (p < 0.05), arthralgias (p < 0.001), and a sustained response to immunomodulatory therapy (p < 0.05), and less frequently had a concurrent malignancy (p < 0.01). IMPP patients had higher serum creatine kinase values (p < 0.05), more frequent serum Jo-1 (p < 0.03) or SSA/SSA52 autoantibodies (p < 0.05), and less frequent antinuclear antibodies (p < 0.01). IMPP patients with serum Jo-1/antisynthetase antibodies were more likely to have ILD (p < 0.05) and inflammatory arthritis (p < 0.05) than IMPP patients without these antibodies.ConclusionsIMPP myopathology is associated with an increased risk of ILD, Raynaud phenomenon, mechanic's hands, and inflammatory arthritis when compared with another immune myopathy (DM-VP). IMPP patients require regular screening for ILD, particularly those with antisynthetase antibodies. The absence of myositis-specific autoantibodies in a large percentage of IMPP patients emphasizes the important role for myopathology in identifying patients at higher risk of severe comorbid conditions such as ILD.

The authors reviewed charts of 78 myelopathy patients who underwent spinal angiography for possible arteriovenous malformations (AVMs). Twenty-two patients had an AVM. No neurologic complications from angiography were observed. MRI findings of increased T2 signal or flow voids were strongly associated with AVMs. Spinal angiography should be performed in all patients with unexplained myelopathy after neurologic evaluation and an MRI demonstrating increased T2 signal or flow voids.

Background: In the standard neurologic examination, outcome measures of sensation testing are typically qualitative and subjective. The authors compared the outcome of vibratory sense evaluation using a quantitative Rydel-Seiffer 64 Hz tuning fork with qualitative vibration testing, and two other features of the neurologic evaluation, deep tendon reflexes and sensory nerve conduction studies. Methods: The authors studied 184 subjects, including 126 with Waldenstrom’s macroglobulinemia and 58 controls, over the course of a weekend. Standard neurologic examinations and quantitative vibratory testing were performed. Sensory nerve action potentials (SNAP) were tested as a measure of sensory nerve function. Tests were carried out by different examiners who were blinded to the results of other testing and to clinical information other than the diagnosis of Waldenstrom’s macroglobulinemia. Results: Quantitative vibration measurements in all body regions correlated with sural SNAP amplitudes. Quantitative vibration outcomes were more strongly related to sural SNAP results than qualitative evaluations of vibration. Quantitative vibration testing also detected a loss of sensation with increased age in all body regions tested. Conclusions: Quantitative vibratory evaluation with Rydel-Seiffer tuning fork is rapid, has high inter- and intrarater reliability, and provides measures for evaluating changes in sensory function over time. Examinations with the quantitative tuning fork are also more sensitive and specific than qualitative vibration testing for detecting changes in sensory nerve function. Use of the quantitative tuning fork takes no more time, provides more objective information, and should replace the qualitative vibratory testing method that is now commonly used in the standard neurologic examination.

A 51-year-old woman with a history of hypertension and smoking presented with sudden onset of confabulation, delusions, and blunted affect. She was oriented to time, place, and person with intact language, strength coordination, and sensation. Gait was slow and wide-based. Serum and CSF yielded no abnormalities. Brain MRI showed bilateral caudate infarcts (figure 1). Cerebral angiography did not provide evidence of dissection or stenosis of the internal carotid artery or major atherosclerosis intracranially or involving the aortic arch. However, it showed an embolus in the right A1, with congenital absence of the left A1 segment; there was a thrombus at the origin of the right internal carotid artery (figure 2). No source of thromboembolism was identified on transthoracic echocardiography. Infarction spared the more distal cortical branches of anterior cerebral artery territories because these benefited from a retrograde filling through middle cerebral artery and posterior cerebral artery pial collaterals, more developed on the left. This congenital vascular variant, one that clinicians should be cognizant of, leads to the bilateral nature of the infarcts.1,2

We identified five patients with IgM monoclonal autoantibodies that bound to human brain tubulin.In a companion study, we found that IgM in these sera selectively recognized one of three epitopes on tubulin. IgM from three patients bound selectively to a small epitope on human beta-tubulin comprising amino acids 301 to 314. The other two sera recognized tubulin amino acids 215 to 235 and 315 to 336. In this study, we compared the clinical syndromes in these patients with the tubulin epitope recognized by their serum IgM. The three patients with IgM binding to tubulin amino acids 301 to 314 all had chronic inflammatory demyelinating polyneuropathy (CIDP) syndromes with slowly progressive weakness, hyporeflexia, and electrophysiologic studies consistent with demyelination. Two of these patients had significant asymmetry to their weakness. The two other patients had diagnoses of polyradiculopathy and amyotrophic lateral sclerosis with no evidence of peripheral nerve demyelination. We conclude that IgM monoclonal anti-tubulin antibodies have some association with demyelinating polyneuropathy syndromes, but may occur in patients with other clinical syndromes as well. A stronger association with demyelinating polyneuropathies may occur if the anti-tubulin antibodies recognize the 301 to 314 amino acid epitope on tubulin. This tubulin epitope, or a similar one on another molecule, could play an important antigenic role in the development of demyelinating polyneuropathies with features of CIDP. NEUROLOGY 1997;48: 243-248

Chronic inflammatory demyelinating neuropathy (CIDP) is a rare disease in childhood.We reviewed the clinical characteristics, response to therapy, and long-term prognosis in 13 children (1.5 to 16 years of age) diagnosed with CIDP at Washington University Medical Center, St. Louis, and the Royal Children's Hospital, Melbourne, Australia, between 1979 and 1994. The most common presenting symptom (in 11/13 [85%]) was lower extremity weakness associated with difficulty in walking. Preceding events within 1 month of onset, mostly intercurrent infections or vaccinations, occurred in seven children (54%). The disease was monophasic in three children (23%). One relapse occurred in four (30%) and multiple relapses in six (46%). All patients had at least short-term response to steroids. Three children (23%) recovered completely during the first year. Ten children (77%) had residual weakness after an average follow-up of 6 years. There seems to be two populations of children with CIDP. One subgroup, with a favorable prognosis, progressed to peak disability over less than 3 months; these children often have a monophasic course with complete resolution of symptoms and signs and withdrawal from all medications by 1 year after onset. A second subgroup progressed for 3 months or longer; these children all required substantial doses of prednisone for prolonged periods and had considerable long-term morbidity with persistent weakness.NEUROLOGY 1996;47: 98-102

Congenital muscular dystrophy syndromes are characterized by congenital weakness, contractures, and dystrophic features on muscle biopsy. However, these syndromes are often difficult to diagnose precisely because their clinical and pathologic characteristics are not specific and resemble changes in other myopathies. We examined muscle biopsies from 20 children with a congenital muscular dystrophy syndrome. Disease controls with dystrophies or other myopathies (n=19) and normal individuals (n=15) were studied for comparison. In each biopsy we determined (1) numbers of muscle fibers with alkaline phosphatase (AlkP) staining, (2) numbers of acid phosphatase-(AcP) positive cells, (3) dystrophin levels by immunocytochemistry, and (4) the distribution of merosin and laminin-A staining. A ratio of AcP:AlkP staining was calculated for each biopsy. In nine patients with congenital muscular dystrophy (younger than 4 years of age) with normal dystrophin, the AcP:AlkP ratio was low (0.09 +/- 0.03). In contrast, in Duchenne muscular dystrophy, the AcP:AlkP ratio was 15 times higher (1.6 +/- 0.04, p=0.001). The three children with congetial muscular dystrophy syndromes and reduced dystrophin and one child with facioscapulohumeral dystrophy had AcP:AlkP ratios in the range of Duchenne muscular dystrophy patients (2.4 +/- 1.4). Low Ac:AlkP ratios were related to relative absence of AcP-positive cells. Merosin staining was absent in 5 of the 17 congenital muscular dystrophy biopsies tested. None of the 5 children with merosin-negative but all 12 with merosin-positive stains walked (p=0.0002). We conclude that a pattern of few AcP-positive cells in the setting of numerous AlkP staining muscle fibers has specificity for congenital muscular dystrophy syndromes and provides histopathologic support for the diagnosis. Reduced merosin in muscle predicts more severe weakness and long-term disability.