Waking up from a nap, 7 1/2-month-old Samantha Dodaro scans her family's den with big brown eyes.  They settle on a visitor.  She smiles.

With her rosy cheeks and contented giggle, Samantha looks like a typical baby.  But she isn't.

She can't sit up.  She can't crawl.  She can't hold up her head.  Chances are, she never will.

Samantha was diagnosed three months ago with Spinal Muscular Atrophy, or SMA, a genetic disease that restricts voluntary muscle movements, even swallowing.  SMA is the No. 1 genetic killer of children younger than 2, according to Families of Spinal Muscular Atrophy, a fund-raising and support group.

Samantha probably won't live to see her second birthday, doctors say.

But her parents, Jim and Wanda Dodaro of Cherry Valley, are hoping their daughter will prove the doctors wrong.

"There are kids out there who have lived past 2 years and we have hope that she'll be one of them," said Jim Dodaro, 38, a computer software engineer.

The couple have joined local fund-raising efforts and their experience sparked a community drive for research money.  The Yucaipa real estate office where Wanda worked is collecting donations and will match the total raised.

"It'd be easier if you could look at her (Samantha) and see there's a problem.  But she's as pink and sweet as a baby girl's supposed to be," said Debi Glaser, who is organizing the fund-raising drive.  "It's just a very sad situation."

The Dodaros are hopeful now after several emotionally draining months following the diagnosis.

"We went through all the stages of grief-denial, anger and finally acceptance.  It's almost like a death.  You have people bringing food and offering support.  Then you get back on your feet and say 'Let's deal with it,'" Jim said.

He has learned everything he can about the disease.  He knows the lingo, the statistics, the symptoms.  He uses the Internet to track drug trials and communicate with doctors doing SMA research.

The first hint that something was wrong came at about 3 months, when Samantha wasn't meeting the basic milestones for her age.  She didn't raise her head or kick her feet in the air.

The baby's doctor contacted a pediatric neurologist at Loma Linda University Medical Center who performed several nerve tests and a genetic sample that confirmed what the family feared.

SMA is usually caused by a defective gene inherited from both parents, and there is a 1 in 4 chance the disease will be passed to a child.  One in 40 people carry the gene, which affects on in every 6,000 newborns.

In about 5 percent of cases, the gene mutates rather than being inherited.  The Dodaros are awaiting genetic test results to see if they are carriers, which will help them decide whether to have more children.

SMA destroys nerve cells in the spinal cord that convey messages between the brain and muscles.

Samantha's head must always be supported, like a newborn.  Her breathing will become more labored as she grows because her chest muscles will weaken.  She eventually may need a respirator.

A cold is the biggest threat to her health now because most children with Type 1 SMA die from respiratory infections.  That's why Wanda quit her job to stay home with Samantha and keep her away from germs.

Several times a day, Wanda stretches Samantha's legs to prevent the muscles from constricting, places toys on an overhead bar and encourages her to grasp them, and takes her in the spa so she can move freely.

"We have to keep believing they're going to find a cure or a drug treatment", said Wanda, 36.  "When they do, she'll be ready."