New Practice Guidelines Recommends Screening Couples for SMA

Spinal muscular atrophy (SMA) is a severe neuromuscular disease caused by mutations in the survival of motor neuron 1 (SMN1) gene. New guidelines recommend that screening for carriers of the mutations in the recessive SMA gene should be made available for all couples.

An accurate genetic test is available for detecting the SMN1 gene mutation that causes SMA. In the past, these tests were mainly offered to families with a child affected by SMA; individuals without a history of the disorder were not tested. The only way to identify couples at high risk of carrying the abnormal SMN1 genes is by DNA testing.

Mutations in the SMN1 gene cause degeneration of motor neurons in the spinal cord, leading to progressive muscle weakness and paralysis. Children with the most common and severe type of SMA (type I, also called Werdnig-Hoffman syndrome) have severe, generalized muscle weakness, usually leading to death from respiratory failure before age two. Other types of SMA are less severe, but are also serious and disabling.

The new practice guideline was issued by the American College of Medical Genetics (ACMG). A statement in the November 2008 issue of Genetics in Medicine, the official journal of the ACMG, recommends, "Because SMA is a common genetic disorder in all populations, carrier testing should be offered to all couples regardless of race or ethnicity." The statement was authored by Thomas W. Prior, Ph.D., professor at Ohio State University (Columbus, Ohio, USA).

SMA testing is to be voluntary and formal genetic counseling will be made available to everyone requesting the testing.

Related Links:
American College of Medical Genetics
Ohio State University