LOS ANGELES (CBSLA.com) — A San Fernando Valley couple finally has answers about the rare and devastating brain disorder their little girl has thanks to a genetic test.

Jennifer and Brian Greene’s 3-year-old daughter Madison can’t walk on her own, has never spoken a single word, and has severe cognitive and developmental delays.

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“Now, we’re fighting for her life. I mean, all of our dreams of having a little girl have been washed away,” said Jennifer Greene, her mother.

Her parents explain that when Madison was born in 2012, they had no indication that anything was wrong.

“We took her home thinking we had a perfectly healthy baby,” she said.

But when she started missing her milestones, the Greenes started to worry. Then at 6 months old, Madison was hospitalized after having a seizure.

Doctors told them Madison had a lack of development in her brain but could not tell them why.

“We wanted answers,” said her mother.

“Without a diagnosis, we’re left to only treating symptoms and saying, ‘I don’t know,’ ” said Dr. Valerie Watiker, Madison’s geneticist.

For two and a half years, test after test came inconclusive. Finally, a doctor suggested the whole-exome sequencing test, a more comprehensive look at a person’s genes used to identify rare, genetic disorders.

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“Genetics is a puzzle and you need all the pieces of your puzzle,” said Watiker.

The test finally revealed Madison has Beta-propeller Protein-Associated Neurodegeneration, an NBIA Disorder (Neurodegeneration with Brain Iron Accumulation), or BPAN. There are only 55 recorded cases in the world to date.

“It’s progressive and she’s going to suffer and her life will be shortened,” Greene said.

Armed with the diagnosis, Greene left her full-time job to devote her life to raising money and awareness, hoping to find a cure for Madison.

“A lot of the drug companies, it’s not necessarily financially beneficial to them to spend money on research trying to develop a cure or treat symptoms because it is so rare,” said Brian Greene, Madison’s father.

The whole-exome test the Greenes did costs about $20,000 and many insurance companies don’t cover it.

The Greenes hope more families have access to it so that they too can know what they are up against.

“We cannot watch her suffer and we have to find a treatment for her,” Greene said.

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For more information on the family’s efforts to raise funds and awareness, click here. To follow Madison’s progress on Facebook, click here.