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Melissa C Keinath,1 Devin E Prior,2 Thomas W Prior1 1Pathology, University Hospitals Center for Human Genetics, Cleveland, OH, USA; 2Neurology, Mount Auburn Hospital, Cambridge, MA, USACorrespondence: Thomas W Prior Email Thomas.Prior@UHhospitals.orgAbstract: Spinal muscular atrophy (SMA) is a heritable neuromuscular disorder that causes degeneration of the alpha motor neurons from anterior horn cells in the spinal cord, which causes severe progressive hypotonia and muscular weakness. With a carrier frequency of 1 in 40– 50 and an estimated incidence of 1 in 10,000 live births, SMA is the second most common autosomal recessive disorder. Affected individuals with SMA have a homozygous loss of function of the survival motor neuron gene SMN1 on 5q13 but keep the modifying SMN2 gene. The most common mutation causing SMA is a homozygous deletion of the SMN1 exon 7, which can be readily detected and used as a sensitive diagnostic test. Because SMN2 produces a reduced number of full-length transcripts, the number of SMN2 copies can modify the clinical phenotype and as such, becomes an essential predictive factor. Population-based SMA carrier screening identifies carrier couples that may pass on this genetic disorder to their offspring and allows the carriers to make informed reproductive choices or prepare for immediate treatment for an affected child. Three treatments have recently been approved by the Food and Drug Administration (FDA). Nusinersen increases the expression levels of the SMN protein using an antisense oligonucleotide to alter splicing of the SMN2 transcript. Onasemnogene abeparvovec is a gene therapy that utilizes an adeno-associated virus serotype 9 vector to increase low functional SMN protein levels. Risdiplam is a small molecule that alters SMN2 splicing in order to increase functional SMN protein. Newborn screening for SMA has been shown to be successful in allowing infants to be treated before the loss of motor neurons and has resulted in improved clinical outcomes. Several of the recommendations and guidelines in the review are based on studies performed in the United States.Keywords: spinal muscular atrophy, carrier screening, newborn screening, SMA treatment

INTRODUCTION: This study aimed to identify infections in patients with myasthenia gravis, dermatomyositis and chronic inflammatory demyelinating polyradiculoneuropathy and investigate the relationship between infection and immunomodulation. METHODS: A retrospective chart review examined 631 patients with myasthenia gravis (n=358), chronic inflammatory demyelinating polyradiculoneuropathy (n=124), and dermatomyositis (n=149) patients over a 10 year time period. RESULTS: Infection rates were similar at approximately 19% in all three diseases. Of the infections in which a causative organism was identified, pneumonia, sepsis, and opportunistic infections were leading diagnoses. A multivariate model demonstrated a significant association between infection and an increased dose of plasma exchange, mycophenolate mofetil, and corticosteroid therapy. DISCUSSION: There are few large studies investigating rates of infections in patients with autoimmune neuromuscular disorders and the relationship to immunomodulation. This study not only demonstrates the remarkably similar infection rates across the three diseases studied, but also shows their relationship to commonly used immunotherapies.