Recessive DES cardio/myopathy without myofibrillar aggregates: intronic splice variant silences one allele leaving only missense L190P-desmin.

We establish autosomal recessive DES variants p.(Leu190Pro) and a deep intronic splice variant causing inclusion of a frameshift-inducing artificial exon/intronic fragment, as the likely cause of myopathy with cardiac involvement in female siblings. Both sisters presented in their twenties with slowly progressive limb girdle weakness, severe systolic dysfunction, and progressive, severe respiratory weakness. Desmin is an intermediate filament protein typically associated with autosomal dominant myofibrillar myopathy with cardiac involvement. However a few rare cases of autosomal recessive desminopathy are reported. In this family, a paternal missense p.(Leu190Pro) variant was viewed unlikely to be causative of autosomal dominant desminopathy, as the father and brothers carrying this variant were clinically unaffected. Clinical fit with a DES-related myopathy encouraged closer scrutiny of all DES variants, identifying a maternal deep intronic variant within intron-7, predicted to create a cryptic splice site, which segregated with disease. RNA sequencing and studies of muscle cDNA confirmed the deep intronic variant caused aberrant splicing of an artificial exon/intronic fragment into maternal DES mRNA transcripts, encoding a premature termination codon, and potently activating nonsense-mediate decay (92% paternal DES transcripts, 8% maternal). Western blot showed 60-75% reduction in desmin levels, likely comprised only of missense p.(Leu190Pro) desmin. Biopsy showed fibre size variation with increased central nuclei. Electron microscopy showed extensive myofibrillar disarray, duplication of the basal lamina, but no inclusions or aggregates. This study expands the phenotypic spectrum of recessive DES cardio/myopathy, and emphasizes the continuing importance of muscle biopsy for functional genomics pursuit of 'tricky' variants in neuromuscular conditions.

Warts and all: Fingolimod and unusual HPV-associated lesions.

BACKGROUND: Fingolimod is used to reduce relapse rates in relapsing-remitting multiple sclerosis (MS). It is a sphingosine 1-phosphate (S1P) analogue having antagonistic effects on S1P receptors. Its immunosuppressive effect is due to reduced circulating lymphocyte numbers, and it may also be associated with impaired intrinsic cancer surveillance. Fingolimod side effects include increased rates and severity of viral infections particularly varicella zoster. METHODS: We present five cases of chronic and treatment refractory warts associated with fingolimod therapy. RESULTS: Each of the five cases presenting with chronic warts while receiving fingolimod therapy had prolonged periods of lymphopenia and improvements were seen following dose reduction or cessation of fingolimod. CONCLUSION: Cutaneous warts are associated with human papilloma virus (HPV) infection, suggesting an increased risk of other HPV-driven conditions such as cervical cancer following fingolimod administration. HPV viruses are responsible for approximately 90% of cervical cancers as well as a significant portion of anogenital cancers and have a high prevalence in sexually active adults. Given the reduced immune response to viral infections and potential impaired cancer surveillance in those receiving fingolimod, HPV vaccination and frequent assessment for the development of HPV-associated malignancies are recommended.

Sarcolemmal excitability in the myotonic dystrophies.

INTRODUCTION: Chloride conductance disturbances contribute to sarcolemmal dysfunction in myotonic dystrophy type 1 (DM1) and type 2 (DM2). Studies using muscle velocity recovery cycles (MVRCs) suggest Na+ /K+ -adenosine triphosphatase activation becomes defective in advanced DM1. We used MVRCs to investigate muscle excitability in DM1 and DM2. METHODS: MVRCs were measured for patients with mild (n = 8) and advanced (n = 11) DM1, DM2 (n = 4), and normal controls (n = 30). RESULTS: Residual supernormality after multiple conditioning stimuli was increased in DM2 and advanced DM1. Advanced DM1 was distinguished by increases in muscle relative refractory period (MRRP) and reduced early supernormality as well as peak amplitude decrements for the first and last responses in train during repetitive stimulation. DISCUSSION: Prolongation of the MRRP indicates that depolarization of the resting muscle membrane potential occurs in advanced DM1, with possible implications for future therapeutic approaches. Muscle Nerve 57: 595-602, 2018.

Use of Whole-Exome Sequencing for Diagnosis of Limb-Girdle Muscular Dystrophy: Outcomes and Lessons Learned.

IMPORTANCE: To our knowledge, the efficacy of transferring next-generation sequencing from a research setting to neuromuscular clinics has never been evaluated. OBJECTIVE: To translate whole-exome sequencing (WES) to clinical practice for the genetic diagnosis of a large cohort of patients with limb-girdle muscular dystrophy (LGMD) for whom protein-based analyses and targeted Sanger sequencing failed to identify the genetic cause of their disorder. DESIGN, SETTING, AND PARTICIPANTS: We performed WES on 60 families with LGMDs (100 exomes). Data analysis was performed between January 6 and December 19, 2014, using the xBrowse bioinformatics interface (Broad Institute). Patients with LGMD were ascertained retrospectively through the Institute for Neuroscience and Muscle Research Biospecimen Bank between 2006 and 2014. Enrolled patients had been extensively investigated via protein studies and candidate gene sequencing and remained undiagnosed. Patients presented with more than 2 years of muscle weakness and with dystrophic or myopathic changes present in muscle biopsy specimens. MAIN OUTCOMES AND MEASURES: The diagnostic rate of LGMD in Australia and the relative frequencies of the different LGMD subtypes. Our central goals were to improve the genetic diagnosis of LGMD, investigate whether the WES platform provides adequate coverage of known LGMD-related genes, and identify new LGMD-related genes. RESULTS: With WES, we identified likely pathogenic mutations in known myopathy genes for 27 of 60 families. Twelve families had mutations in known LGMD-related genes. However, 15 families had variants in disease-related genes not typically associated with LGMD, highlighting the clinical overlap between LGMD and other myopathies. Common causes of phenotypic overlap were due to mutations in congenital muscular dystrophy-related genes (4 families) and collagen myopathy-related genes (4 families). Less common myopathies included metabolic myopathy (2 families), congenital myasthenic syndrome (DOK7), congenital myopathy (ACTA1), tubular aggregate myopathy (STIM1), myofibrillar myopathy (FLNC), and mutation of CHD7, usually associated with the CHARGE syndrome. Inclusion of family members increased the diagnostic efficacy of WES, with a diagnostic rate of 60% for "trios" (an affected proband with both parents) vs 40% for single probands. A follow-up screening of patients whose conditions were undiagnosed on a targeted neuromuscular disease-related gene panel did not improve our diagnostic yield. CONCLUSIONS AND RELEVANCE: With WES, we achieved a diagnostic success rate of 45.0% in our difficult-to-diagnose cohort of patients with LGMD. We expand the clinical phenotypes associated with known myopathy genes, and we stress the importance of accurate clinical examination and histopathological results for interpretation of WES, with many diagnoses requiring follow-up review and ancillary investigations of biopsy specimens or serum samples.

Replication of association between ELAVL4 and Parkinson disease: the GenePD study.

Genetic variants in embryonic lethal, abnormal vision, Drosophila-like 4 (ELAVL4) have been reported to be associated with onset age of Parkinson disease (PD) or risk for PD affection in Caucasian populations. In the current study we genotyped three single nucleotide polymorphisms in ELAVL4 in a Caucasian study sample consisting of 712 PD patients and 312 unrelated controls from the GenePD study. The minor allele of rs967582 was associated with increased risk of PD (odds ratio = 1.46, nominal P value = 0.011) in the GenePD population. The minor allele of rs967582 was also the risk allele for PD affection or earlier onset age in the previously studied populations. This replication of association with rs967582 in a third cohort further implicates ELAVL4 as a PD susceptibility gene.

Intracranial and dermatological cryptococcal infection in an immunocompetent man.

We report the case of a 72-year-old man with a history of Parkinson's Disease who presented with a history of falls, cognitive impairment and depressed mood. Neurological examination revealed moderate rigidity and bradykinesia. Alterations to his anti-Parkinsonian medication resulted in improvements in his mobility but no change in mental state. He was also noted to have developed multiple raised skin lesions. One of these lesions was biopsied and grew Cryptococcus neoformans. He subsequently had a cerebral MRI scan which showed enhancing lesions, in the left parietal lobe and right superior cerebellar peduncle, consistent with intracranial cryptococcal infection. Images of one of the skin lesions and the cerebral MRI scan are shown.

Identifying the pattern of olfactory deficits in Parkinson disease using the brief smell identification test.

BACKGROUND: Selective olfactory deficits occur in 70% to 90% of patients with Parkinson disease, independent of disease severity and duration. Olfactory testing may be a useful diagnostic aid for Parkinson disease, but the types of odors most commonly affected need to be identified. OBJECTIVE: To determine the pattern and types of odors affected in Parkinson disease by means of the University of Pennsylvania 12-item Brief Smell Identification Test (B-SIT; Sensonics, Inc, Haddon Heights, NJ). DESIGN: Testing patients with Parkinson disease and control subjects in 5 movement disorder clinics. PARTICIPANTS: Forty-nine nondemented patients with Parkinson disease and 52 age- and sex-matched controls. MAIN OUTCOME MEASURES: Normal or abnormal olfactory function was determined in each subject according to predetermined age and sex norms. Predictive statistics and discriminant function analyses were performed to determine the pattern and types of odors best discriminating patients from controls. RESULTS: Abnormal olfactory function was present in 40 (82%) of patients compared with 12 (23%) of controls. The B-SIT score was unaffected by smoking behavior, disease duration, or severity. The sensitivity of the B-SIT for Parkinson disease was 0.82, with a specificity and predictive value of 0.82 and 0.77, respectively. Only 5 of the 12 B-SIT odors (gasoline, banana, pineapple, smoke, and cinnamon) were required to adequately discriminate patients with Parkinson disease from controls. CONCLUSIONS: With the use of the B-SIT, 5 specific odors appear primarily affected in patients with Parkinson disease. Significantly, the ability of patients to detect some odors was unimpaired compared with that of controls. Better diagnostic aids could be developed on the basis of the selective pattern of hyposmia observed in Parkinson disease.