Update - 9/9/21 - Adding Spinal Muscular Atrophy (SMA) to the Newborn Screening Panel
In addition, the Iowa Newborn Screening Program has completed the required administrative rule process to begin statewide newborn screening for SMA effective September 13, 2021.
SMA testing and clinical notification will be done through the Iowa, North Dakota, and South Dakota contract laboratory, the State Hygienic Laboratory at the University of Iowa.
What is SMA?
SMA is a progressive neurodegenerative disease that affects the motor nerve cells in the spinal cord and impacts the muscles used for activities such as breathing, eating, crawling, and walking.
SMA is caused by mutation in the Survival Motor Neuron 1 (SMN1) gene. SMN1 is needed for normal development and maintenance of motor nerve cells located in the brainstem and spinal cord. In people that have a SMN1 mutation, motor nerve cells do not function properly and eventually die. Loss of motor neurons leads to progressive skeletal muscle weakness which includes breathing and swallowing.
Early treatment of babies with infantile onset SMA is needed to avoid progressive muscle weakness and respiratory failure. Without treatment, the infantile form of SMA typically leads to death in the first two years of life. Untreated later-onset forms of SMA lead to physical disability due to progressive muscle weakness. Treatment for infantile-onset SMA includes medication to assist the underlying genetic abnormality, as well as respiratory, rehabilitative, and nutritional therapy.
Newborn screening for SMA involves identification of an absence of exon 7 in the SMN1 gene. Loss of SMN1 exon 7 is the causative mutation in 95% of SMA cases. However, there are 5% of mutations in SMA that are not caused by loss of SMN1 exon 7.
A reminder, this is a screening test. A false negative or a false positive result must always be considered when screening. Therefore, clinical findings and status should be considered whenever interpreting newborn screening results.
Please see this document for reporting information pertaining to SMA testing.
