August is “SMA Awareness Month”
In an attempt to express interest in my career, my husband likes to send me interesting links to news stories and videos that relate to genetics. He likes even more to send me links to his fantasy baseball players’ accomplishments. This week was his crowning achievement, as he sent me one that combined genetics and baseball. It was a video and article from ESPN.com about a 6 year old boy and his twin sister, both of whom have spinal muscular atrophy (SMA). The boy’s dream was to play for the Arizona Diamondbacks. The video is incredible and is a real tear-jerker!
If you or your partner has been pregnant in the past few years, you might have heard of SMA since your OB/GYN may have offered you genetic testing for this condition. SMA is an inherited disease of the motor nerves that causes muscle weakness and atrophy (wasting). Motor nerves arise from the spinal cord and control the muscles that are used for activities such as breathing, crawling, walking, head and neck control, and swallowing. So if the motor nerves are not working properly, these bodily functions are compromised. In his book “Genetic Rounds,” pediatric geneticist Dr. Robert Marion (Einstein) describes SMA as “the childhood equivalent of the better-known, but also poorly understood, amyotrophic lateral sclerosis, more commonly known as Lou Gehrig’s disease…” (pgs 85-86). SMA is a rare disorder occurring in approximately 8 out of every 100,000 live births, and is the leading cause of infant death. There are four types of SMA, which range from lethal in infancy to a less severe form that develops in adulthood.
Like other Ashkenazi Jewish diseases we have talked about on this blog, SMA is inherited in an autosomal recessive pattern. So if both parents in a couple are carriers of SMA, there is a 1 in 4 chance for them to have a child who is affected.
The reason many OB/GYNs order SMA testing is because in 2008, the American College of Medical Genetics and Genomics came out with a Practice Guideline that said: “Because SMA is present in all populations, carrier testing should be offered to all couples regardless of race or ethnicity.” Recent studies have shown that the carrier frequency is about 1 in 56 in the general population, and about 1 in 67 in the Ashkenazi Jewish population.
If you look at our current panel of diseases for screening our Ashkenazi patients, you will see that based on carrier frequency, SMA is actually more common than many of the other diseases on the panel. I would like to point out that even though it is more common, SMA does not fall under the category of “Ashkenazi Jewish genetic diseases.” This is because those conditions have known “founder mutations,” or genetic changes that are frequent in that specific population. SMA mutations are common in ALL populations, not just in Ashkenazi Jews. Since we often see patients who come for Ashkenazi testing before a pregnancy, we recommend that they also get screened for SMA at the same time. This is also true for the Sephardic and non-Jewish patients we see.
August is “SMA Awareness Month.” To learn more about SMA and the research initiatives to treat it, go online to the SMA Foundation website. Personally, I am made aware of SMA every day since my neighbor is affected with type II SMA and I see her playing outside in her wheelchair all the time. But for those of you who do not know anyone who is affected, try to become aware that this condition exists. Make sure to get screened before a pregnancy or early into one, and spread the word to your child-bearing friends and family. You could really make the difference!
Posted on August 22, 2013, in Estie's posts and tagged Arizona Diamondbacks, Ashkenazi Jewish, Dr. Robert Marion, ESPN, genetic counseling, Genetic Rounds, Program for Jewish Genetic Health, SMA. Bookmark the permalink. 2 Comments.