Spinal Muscular Atrophy

With an incidence of approximately 1 in 10,000 live births and a carrier frequency of 1/40–1/60, SMA is the leading inherited cause of infant mortality.¹

SMA (Spinal Muscular Atrophy) is a genetic disorder characterized by the degeneration of motor neurons in the spinal cord. It leads to muscle weakness and atrophy, impacting the individual's ability to control movement. MLPA (Multiplex Ligation-dependent Probe Amplification) is a genetic testing method that can be used for SMA testing. MLPA specifically allows for the detection of deletions or duplications in the SMN1 & SMN2 gene, which is the primary causative gene for SMA.

MLPA-based testing for SMA is a reliable and efficient method for detecting SMN1 & SMN 2 gene deletions or duplications. It provides valuable information for diagnosis, carrier testing, and family planning for individuals at risk of SMA. It is important to consult with healthcare professionals, such as genetic counselors or medical geneticists, who can guide individuals in the appropriate use and interpretation of MLPA testing for SMA.

When should you get tested?

• When there is a clinical suspicion of SMA based on symptoms such as muscle weakness, motor delays, or a family history of SMA.
• Individuals who are planning to have children and want to determine if they are carriers of the SMA gene.
• Pregnant women who are known carriers of the SMA gene or have a family history of SMA.
• Couples who have previously had a child with SMA or have a family history of SMA. It helps in assessing the risk of SMA recurrence in future pregnancies and guides family planning decisions.
• In some cases, SMA testing may be recommended as part of population screening programs, especially in regions or communities with a higher prevalence of SMA.

Test specification

References:

1. Prior, T., Nagan, N., Sugarman, E. et al. Technical standards and guidelines for spinal muscular atrophy testing. Genet Med 13, 686–694 (2011). https://doi.org/10.1097/GIM.0b013e318220d523