Detecting SMA With Carrier Screening

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by Wendy Henderson |

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The decision to screen for genetic diseases like spinal muscular atrophy or cystic fibrosis is very personal. Generally speaking, only those who are at risk of being a carrier due to a family history of SMA or a similar disease are advised to undergo screening before starting a family, but anyone may choose to do so.

MORE: Study reveals views of SMA patients and families about genetic screening

According to the UCSF Medical Center, SMA is caused by a mutation of the survival motor neuron 1 gene (SMN1). A carrier of SMA will have one copy of the mutated gene and one copy of the healthy SMN1 gene. For a baby to have the condition, they must inherit a copy of the mutated gene from each parent.

There is a one in 50 chance that a person will be a carrier of SMA. If both parents have a copy of the mutated SMN1 gene then there is a 25 percent chance that each child they have will inherit SMA.

Prenatal screening is also available for couples who are at risk of having a baby with SMA and is usually conducted between 10 and 14 weeks. Couples wishing to undergo screening for SMA are advised to have counseling prior to the test.

A new screening test for SMA and other genetic diseases has been launched in Europe and South America. The test will be offered in select countries including Italy, Portugal, Spain, Switzerland, and Colombia. According to Cure SMA, genetic tests can detect 90 percent of carriers except for in African-Americans, where the detection rate drops to 70 percent.

MORE: Good Start Genetics and Roche join to make screening tool available for mothers-to-be.

SMA News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.