(CNN) — Their daughter Mia was just three years old when Canadian couple Edith Lemay and Sebastien Pelletier first noticed that she was having vision problems.
A few years after they first took her to see a specialist, Mia, the eldest of their four children, was diagnosed with retinitis pigmentosa, a rare genetic condition that causes a loss or decline in vision over time.
By this point, Lemay and Pelletier, who’ve been married for 12 years, had noticed that two of their sons, Colin, now seven, and Laurent, now five, were experiencing the same symptoms.
Their fears were confirmed when in 2019 the boys were diagnosed with the same genetic disorder; their other son Leo, now nine, was given the all clear.
“There’s nothing you can really do,” says Lemay, explaining that there is currently no cure or effective treatment to slow down the progression of retinitis pigmentosa.
“We don’t know how fast it’s going to go, but we expect them to be completely blind by mid-life.”