Why focus on SMA screening?
The purpose of SMA carrier screening is to determine if a couple is at increased risk for having a child with SMA, the leading genetic cause of infant death.1
You could be a carrier of SMA even if no one in your family has SMA and even if you already have children without SMA. Carriers of the abnormal gene have no symptoms of the disorder. As with most inherited disorders, the risk for being an SMA carrier varies by ethnic background2 (see table below).
|Ethnicity||SMA carrier risk in people with no family history of SMA|
|Caucasian||1 in 47|
|Asian Indian||1 in 52|
|Asian||1 in 59|
|Ashkenazi Jewish||1 in 67|
|Hispanic||1 in 68|
|African American||1 in 72|
The screening test requires a blood sample or mouthwash and results are typically ready within 5 to 8 days. If a couple has not yet conceived, one partner is usually tested first. If a woman is already pregnant, a couple may opt to be tested at the same time.
If both parents are carriers of an altered SMA gene, there is a chance their child will be affected.
Learn more about how inherited disorders like SMA are passed on.