when destiny mccalvin was pregnant with her son chance, she and her husband justin had every reason to be concerned. two years earlier they had lost their daughter kensley to spinal muscular atrophy (sma) at the age of seven months.
when her daughter was diagnosed at five months, it was the most horrible news any parent could face, mccalvin said. “she had a fatal disorder that we couldn’t do anything about.”
sma is the result of a genetic mutation that leads to devastating outcomes. like other genetic mutations, the parents can be carriers without knowing it.
genetic testing on the mccalvins confirmed that they were both carriers, so their children would have a one in four chance of being born with type 1 sma – the most debilitating and rapidly progressing category of the disease that affects one in 10,000 births per year.
the deterioration for type 1 sufferers begins very early, but the signs are not evident until about three to six months, which is when some parents will begin to notice. awareness of sma is key so parents are quick to follow up when the baby is not reaching its milestones.
“it’s a heartbreaking condition to watch,” said dr. alex mackenzie, pediatrician at children’s hospital of eastern ontario in ottawa. “most type 1 patients succumb to the disease by two years of age, because the muscles involved in breathing are also affected. types 2 and 3 come on later and progress more slowly. people are more familiar with a similar neurodegenerative disorder that more commonly affects adults – lou gehrig’s disease or als.”