Often the first sign of spinal muscular atrophy (SMA) is infants failing to meet development milestones such as supporting their heads, rolling, crawling, etc. This is usually highlighted by the parents or primary care doctor during routine assessments. If babies aren’t meeting their milestones then they will undergo various tests to determine what the problem is.
If SMA is suspected, the following tests will be conducted:
In most cases of SMA, both copies of the SMN1 exon 7 are missing, this can usually be detected through a simple blood test and is the most effective and least invasive way of diagnosing the disease. Parents who both carry the faulty SMN1 gene will have a 25 percent chance of passing the mutation on to their child, which causes SMA. The blood test is accurate in approximately 95 percent of cases but it cannot determine whether the SMA is type, 1, 2, or 3–the time of onset and physical symptoms of the patient will usually determine this. Find out more about genetic testing for SMA here.