CARNIVAL Type I: Valproic Acid and Carnitine in Infants With Spinal Muscular Atrophy (SMA) Type I

Inclusion Criteria: * Laboratory documentation of SMN mutation/deletion consistent with a genetic diagnosis of SMA * Clinical diagnosis of SMA type I * Age 2 weeks to 12 months * Written informed consent of parents/guardian Exclusion Criteria: * Any clinical or laboratory evidence of hepatic or pancreatic insufficiency. * Laboratory results drawn within 14 days prior to start of study drug demonstrating: Liver transaminases (AST, ALT), lipase, amylase: \> 1.5 x ULN White Blood Cell Count: \< 3 Neutropenia: \<1 Platelet: \<100K Hematocrit: \<30, persisting over a 30-day period * Serious illness requiring systemic treatment and/or hospitalization within two weeks prior to study entry. * Use of medications or supplements within 30 days of study enrollment that interfere with VPA or carnitine metabolism; that increase the potential risks of VPA or carnitine; or that are hypothesized to have a beneficial effect in SMA animal models or human neuromuscular disorders, including riluzole, valproic acid, hydroxyurea, oral use of albuterol, sodium phenylbutyrate, butyrate derivatives, creatinine, growth hormone, anabolic steroids, probenecid, oral or parenteral use of corticosteroids at entry, or agents anticipated to increase or decrease muscle strength or agents with presumed histone deacetylase (HDAC) inhibition. * Infants who have participated in a treatment trial for SMA within 30 days of study entry or who will become enrollees in any other treatment trial during the course of this study. * Unwillingness to travel for study assessments. * Coexisting medical conditions that contradict use of VPA/carnitine or travel to and from study site.