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Personalized pre- and post-test counseling support

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Spinal Muscular Atrophy Test

Spinal Muscular Atrophy (SMA) is a set of neuromuscular disorders characterized by skeletal muscle weakness and immobility due to nerve cell degeneration in the spial cord. The condition is primarily caused by genetic alterations in the SMN1 gene, with 95% of cases involving deletions in this gene or additional copies of the related SMN2 gene. First Genomix employs the Multiplex ligation-dependent probe amplification technique to accurately detect SMN1 gene deletions and determine SMN2 gene copy numbers.

How is the test performed?

SMA testing is recommended in the following cases:
  • Couples with a family history of SMA who need to assess the risk of passing on the SMN1 deletion to their offspring
  • All pregnant or prospective couples
  • Fetuses whose parents are identified as carriers. This is done using CVS or Amniocentesis for prenatal diagnosis
  • Individuals exhibiting symptoms of SMA
  • Individuals who have a family member diagnosed with SMA, seeking to verify their carrier status
  • Newborns for screening purposes, to enable early medical intervention

SMA is a serious disease of high carrier frequency and is considered the second most common autosomal recessive disorder globally. Testing helps couples understand their carrier status and their chances of passing SMA genes to their offspring in case of an existing family history, helping inform family planning decisions. Testing can also determine if other family members may have inherited the disease, providing clinicians with in-depth diagnostic information that can guide important clinical decisions.

Genetic results for SMA testing are interpreted as follows:

Carrier Testing:
  • 1 copy of the SMN1 gene detected: Indicates that the patient is a carrier of SMA.
  • 2 copies of the SMN1 gene detected: Suggests that the patient is unlikely to be a carrier of SMA, although the possibility cannot be completely excluded.
Diagnostic Testing:
  • Homozygous deletion (0 copies of SMN1 gene): Confirms a diagnosis of SMA.
  • Heterozygous deletion (1 copy of SMN1 gene detected): Suggests SMA but additional testing may be needed for confirmation, especially if there are rare mutations on the non-deleted copy of the SMN1 gene.
  • No deletion (2 copies of SMN1 gene detected): Indicates that a diagnosis of SMA is unlikely.