Two-year-old Owen Cain cannot lift his head or move his limbs. He’s fed through a tube, and even the simple act of sitting in a chair can trigger an alarming breathing spasm.

The child has Spinal Muscular Atrophy (search), or SMA – the leading genetic killer of infants and toddlers. One in 40 people are carriers and at risk of having an affected child.

“Their disorder is under-recognized, it’s misdiagnosed, it certainly has been under-funded,” said Dr. Darryl De Vivo of Columbia University Medical Center (search).

Owen has Type 1 SMA, the most severe. Thousands of other children have Type 2 or 3, meaning they have more muscle control and a longer life expectancy. But all parents whose children are afflicted face an uphill battle with the disease. Not only is caring for SMA kids difficult, but federal funding for research is scarce.

SMA gets only a tenth of the federal funding of another motor-neuron condition, Lou Gehrig’s Disease (search) – even though the disorders claim the same number of victims per year. With more money, a group of scientists and doctors at the National Institutes of Health (search) believe they could be within two years of finding a cure for SMA.

But despite a letter-writing campaign by desperate parents, NIH funding is relatively low and a cure is still out of reach. Owen’s dad worries that it won’t come soon enough for his little boy.

“It may be too late for Owen,” said Hamilton Cain. “He may always be like this. But we’ve got to try.”

Click the box near the top of the story to watch a report by FOX News' Alisyn Camerota.