One Child's Legacy
A couple's celebration of their daughter's short life and their work to change genetic testing for others
In the month of April, a blog titled Avery’s Bucket List, went viral (averycan.blogspot.com). The entries chronicled several days in the life of Avery Lynn Canahuati, a 5-month old little girl from Texas who was born with spinal muscular atrophy (SMA). Because of her diagnosis, baby Avery was not expected to survive past her second birthday. Suddenly, on April 30, 2012, Avery died after suffering a collapsed lung and cardiac arrest.
But not before the word got out that the cause of her death is not that uncommon. In fact, according to the SMA Foundation, spinal muscular atrophy is the leading genetic cause of death among children under the age of 2. SMA is a genetic disorder caused by a mutated gene, which is responsible for the production of a protein known as SMN1 (survival motor neuron 1). The lack of this protein means baby’s muscles are weak and gradually atrophy, affecting gross motor function, such as walking, as well as respiratory function. Eventually, the lack of SMN1 results in the death of the spinal cord and brain stem.
How common is SMA?
Dr. Namrata Shah, a pediatric neurologist at Le Bonheur Children’s Hospital in Memphis, says she sees about two to three cases of SMA each year, most of which are Type 1. Because there is no cure, Shah says care is based on treating the child’s symptoms and relieving pain. “We generally make a plan with each family,” she says. “The children with SMA have feeding difficulties and respiratory issues. We discuss the prognosis with parents, and decide on a course of treatment that will keep the quality of life as high as possible for the children.”
SMA is an inherited disorder, meaning when two parents are carriers of the gene, a child has a one-in-four chance of being born with the disorder. According to the National Human Genome Research Institute, anywhere from 1 in 6,000 to 1 in 10,000 people are affected by SMA. Shah says unlike other genetic disorders, such as sickle cell anemia or Tay-Sachs, SMA is not more likely to show up in any particular demographic or ethnic group.
Though SMA in its most severe form is almost always fatal, there are actually multiple types of the disorder. Baby Avery suffered from the most severe type of SMA - Type 1 or Werdnig-Hoffmann disease. Infants are generally diagnosed with Type 1 SMA by six months of age with a prognosis of less than two years. Type 2 and Type 3 SMA are less severe, with later onsets and longer life expectancies.
Is testing available?
Due to cost, prenatal and carrier screening are not a part of the typical round of tests given to pregnant women and newborns, though they are available. Most parents, therefore, only know that they are carriers if they have a relative who has had SMA, often a child. Shah says when parents who know they are carriers want to have child, they are strongly advised to go through genetic counseling, as their children will have a 25 percent chance of having SMA. Genetic counselors are medical professionals with graduate training in genetics and counseling. If you need genetic counseling, ask for a recommendation through your OB/GYN or find a genetic counselor through the National Society of Genetic Counselors at nsgc.org.
The Canahuati’s, Avery’s parents, created her blog to honor their daughter’s life and to raise awareness of SMA. Learn more at fightsma.org.