The National ALS Registry: a recruitment tool for research

INTRODUCTION

Subject recruitment is critical for understanding fatal diseases like ALS, however linking patients with researchers can be challenging. The U.S. population-based National ALS Registry allows recruitment of persons with ALS (PALS) for research opportunities.

METHODS

The Registry's Research Notification Mechanism was used to recruit PALS aged ≥21 years; participants completed a Web-based epidemiologic survey. PALS (n = 2,232) were sent an email describing the study, and 268 surveys were completed.

RESULTS

The mean age (± SD) of eligible participants was 57.7 ± 9.3 years for men and 61.5 ± 8.9 for women. Most were men (63%) and Caucasian (92%). Of 256 potentially eligible participants, 37.5% (n = 96) returned an authorization to disclose protected health information. ALS was confirmed for 94% (83/88) from physician responses.

CONCLUSIONS

This analysis demonstrates the National ALS Registry's usefulness in recruiting PALS for research. This recruitment source can potentially foster the discovery of better treatment options and therapies, and of prevention strategies.

Parental attitudes toward newborn screening for Duchenne/Becker muscular dystrophy and spinal muscular atrophy

INTRODUCTION

Disease inclusion in the newborn screening (NBS) panel should consider the opinions of those most affected by the outcome of screening. We assessed the level and factors that affect parent attitudes regarding NBS panel inclusion of Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and spinal muscular atrophy (SMA).

METHODS

The attitudes toward NBS for DMD, BMD, and SMA were surveyed and compared for 2 categories of parents, those with children affected with DMD, BMD, or SMA and expectant parents unselected for known family medical history.

RESULTS

The level of support for NBS for DMD, BMD, and SMA was 95.9% among parents of children with DMD, BMD, or SMA and 92.6% among expectant parents.

CONCLUSIONS

There was strong support for NBS for DMD, BMD, and SMA in both groups of parents. Given advances in diagnostics and promising therapeutic approaches, discussion of inclusion in NBS should continue.

Validity of hospital discharge data for identifying cases of amyotrophic lateral sclerosis

Inpatient hospital encounters and emergency department visits were examined to identify cases of amyotrophic lateral sclerosis (ALS).The ninth edition of the International Classification of Disease, clinical modification (ICD-9-CM) for ALS was confirmed for ALS was confirmed in 93% of inpatient discharges and in 91% of emergency department visits by the diagnostic standard (chart review). Yearly prevalence rates ranged from 2.94 to 3.28 per 100,000 residents. The low calculated prevalence rates suggest that this method of case identification is inadequate and must be combined with other data sets to maximize confirmation of the clinical diagnosis.

Accuracy and usefulness of ICD-10 death certificate coding for the identification of patients with ALS: results from the South Carolina ALS Surveillance Pilot Project

The purpose if this study was to investigate the positive predictive value and sensitivity of the ICD-10 code G12.2, which is used to identify patients who have possibly died from ALS. All patients with a motor neuron disease diagnosis code during the study period (2001-2005) were identified using administrative data. South Carolina death certificate data were used to assess the positive predictive value and sensitivity of the ICD-10 code G12.2. Two hundred and seventy known cases of ALS linked to the death certificate data file. G12.2 was coded as either the underlying or contributing cause of death for 229 cases, sensitivity = 85%. There were 318 deaths due to ALS identified by the G12.2 code where a medical record was available for review. Of those, 205 contained information supporting the diagnosis of ALS, positive predictive value = 65%. This evaluation raises questions concerning the validity of using mortality data in forming epidemiological conclusions in this patient population. However, it does appear that mortality data can be used in the development of case-finding algorithms to identify ALS patients through the use of administrative data sets.

Myasthenic syndrome caused by plectinopathy

BACKGROUND

Plectin crosslinks intermediate filaments to their targets in different tissues. Defects in plectin cause epidermolysis bullosa simplex (EBS), muscular dystrophy (MD), and sometimes pyloric atresia. Association of EBS with a myasthenic syndrome (MyS) was documented in a single patient in 1999.

OBJECTIVES

To analyze the clinical, structural, and genetic aspects of a second and fatal case of EBS associated with a MyS and search for the genetic basis of the disease in a previously reported patient with EBS-MD-MyS.

METHODS

Clinical observations; histochemical, immunocytochemical, and electron microscopy studies of skeletal muscle and neuromuscular junction; and mutation analysis.

RESULTS

An African American man had EBS since early infancy, and progressive muscle weakness, hyperCKemia, and myasthenic symptoms refractory to therapy since age 3 years. Eventually he became motionless and died at age 42 years. At age 15 years, he had a marked EMG decrement, and a reduced miniature endplate potential amplitude. The myopathy was associated with dislocated muscle fiber organelles, structurally abnormal nuclei, focal plasmalemmal defects, and focal calcium ingress into muscle fibers. The neuromuscular junctions showed destruction of the junctional folds, and remodeling. Mutation analysis demonstrated a known p.Arg2319X and a novel c.12043dupG mutation in PLEC1. The EBS-MD-MyS patient reported in 1999 also carried c.12043dupG and a novel p.Gln2057X mutation. The novel mutations were absent in 200 Caucasian and 100 African American subjects.

CONCLUSIONS

The MyS in plectinopathy is attributed to destruction of the junctional folds and the myopathy to defective anchoring of muscle fiber organelles and defects in sarcolemmal integrity.

Neurosarcoidosis

Neurosarcoidosis is an uncommon disorder and requires a careful clinical evaluation to reach a diagnosis. Generally, patients with peripheral symptoms, which include paresthesias, muscle weakness, and stocking glove deficits, have a better outcome compared with those with central nervous system involvement. Patients with mass lesions or hydrocephalus tend to have more relapses and are often more resistant to routine therapy. Neurosarcoidosis often responds to glucocorticoids, usually within days or weeks of initiating therapy. Patients are usually maintained on 40 to 80 mg per day for 4 to 6 weeks, which is then tapered slowly. Alternative treatments for refractory neurosarcoidosis, or to reduce or eliminate steroids, include methotrexate, cyclophosphamide, azathioprine, cyclosporine, infliximab, chlorambucil, chloroquine, and hydroxychloroquine.

Single-fiber electromyography during menstrual exacerbation and ovulatory suppression in MuSK antibody–positive myasthenia gravis

We report a patient with muscle-specific tyrosine kinase (MuSK) antibody-positive myasthenia gravis who experienced worsening of myasthenic weakness associated with alterations in estrogen and progesterone levels during the administration of oral contraceptive therapy. Single-fiber electromyography was performed to document changes in neuromuscular transmission associated with the clinical exacerbation and subsequent resolution of the menstrual exacerbation and clinical improvement experienced with continuous monophasic oral contraceptive therapy. The potential long-term benefit of ovulatory suppression in MuSK antibody-positive myasthenia gravis is discussed.

Peripheral neuropathy in genetic mitochondrial diseases

Peripheral neuropathy is an underrecognized but common occurrence in genetic mitochondrial disorders. To gain insight into the frequency and clinical presentation of this complication, nerve conduction studies were performed on 43 subjects with congenital lactic acidosis enrolled in a controlled clinical trial of oral dichloroacetate. Median and peroneal motor conduction studies and median and sural sensory conduction studies were performed on each patient. The mean amplitude of the peroneal motor nerve (P < 0.001) and the conduction velocities of the median (P < 0.001) and peroneal (P < 0.001) motor nerves were uniformly lower in our subjects than in healthy literature control subjects. There were no significant differences in sensory nerve conduction studies. A generalized reduction in motor nerve conduction velocity was the dominant electrophysiological abnormality in the patients in this study and was independent of age, sex, or congenital mitochondrial disorder. We postulate that cellular energy failure is the most likely common cause of peripheral neuropathy in patients with genetic mitochondrial diseases, owing to the high demand for adenosine triphosphate via aerobic carbohydrate metabolism by nerve tissue.

Sural neuropathy: Etiologies and predisposing factors

Isolated sural neuropathy is an uncommon diagnosis. We identified 36 patients with isolated sural neuropathy. Sixteen had various forms of ankle trauma, in three of whom the associated sural neuropathies developed following medical intervention. Three patients developed sural neuropathy associated with vasculitis, and there were single patients with schwannoma and ganglionic cyst. In patients without a history of trauma, structural causes, such as schwannoma or ganglionic cysts and vasculitis, should be considered and managed as appropriate.

MuSK-antibody positive myasthenia gravis: Clinical and electrodiagnostic patterns

OBJECTIVE

To examine the clinical manifestations and patterns of electromyographic abnormalities in MuSK-Ab positive myasthenia gravis.

METHODS

The clinical evaluations and electrodiagnostic testing results of 20 MuSK-Ab positive myasthenia gravis patients were retrospectively reviewed and compared with matched AChR-Ab positive (N = 72) and MuSK-Ab negative/AChR-Ab negative (N = 24) patients.

RESULTS

MuSK-Ab positive patients were younger and more frequently female and African-American, and compared to the AChR-Ab positive patients, were more likely to present with respiratory symptoms or neck extension weakness. MuSK-Ab positive patients were less likely to have abnormal jitter in a limb muscle: only 59% had abnormal jitter in the extensor digitorum communis muscle, compared to 80% of the AChR-Ab negative/MuSK-negative patients and 91% of the AChR-Ab positive patients.

CONCLUSIONS

Our MuSK-Ab positive patients not only differ demographically from our MuSK-Ab negative cohort, but they also appear to have a more limited distribution of SFEMG abnormalities.

SIGNIFICANCE

The possibility that electrophysiologic abnormalities may not be widely distributed should be considered during electrodiagnostic evaluation of suspected MuSK-Ab positive MG and in selecting muscles for molecular, morphologic, or microphysiologic studies in this condition.

Juvenile-onset Leigh syndrome with an acute polyneuropathy at presentation

Subacute necrotizing encephalomyelopathy or Leigh syndrome can be associated with a polyneuropathy. By far, the most commonly encountered neuropathy is a chronic neuropathy with features of demyelination, which can be the presenting manifestation of Leigh syndrome. On rare occasions, the neuropathy encountered can represent a more acute process. We describe a rare case of juvenile-onset Leigh syndrome presenting with an acute polyneuropathy.