Measuring Levels of SMN in Blood Samples of SMA Patients

Spinal muscular atrophy (SMA) is a currently untreatable, autosomal recessive motor neuron disease that is caused by deficiency of full-length survival motor neuron (SMN) protein. One promising therapeutic approach to SMA is to pharmacologically increase full-length SMN protein levels. Several compounds have been shown to increase SMN levels in immortalized cell lines derived from SMA patients. The objective of this study is to determine baseline SMN levels in primary peripheral blood cells of SMA patients and heterozygous carriers compared to unaffected controls and to investigate the effects in vitro of pharmacological compounds that are expected to increase SMN levels. It is anticipated that these studies will provide further evidence to support the use of one or more of these compounds in a clinical trial for SMA patients. The study population will include patients with genetically proven type I, II, or III SMA and their family members. Blood samples from anonymous, unaffected control patients will be obtained through the department of transfusion medicine (99-CC-0168). This is an investigative study that involves blood drawing only. No new therapy will be provided except the standard of care.