Young couple grapples with daughter's rare genetic disorder

2-year-old girl moves very little, feeds through a tube and sometimes requires oxygen

April 22, 2011|By Frank D. Roylance, The Baltimore Sun

YORK, Pa. — — There was something different about Marisa.

"The moment she was born, she was blowing bubbles," recalled her father, Joel Easterly, 32. "Some of the nurses were saying, 'Wow!' They'd never seen that before."

Bubbles seemed innocuous enough. The pregnancy had gone well, the delivery was quick and Marisa was a healthy 6 pounds 4 ounces.

But it was the first hint of an extremely rare medical ailment that has been reported in about 30 people worldwide. The problem, caused by a genetic deficiency, has exhausted the young family physically, emotionally and financially.

At two months, Marisa was hospitalized for a week. "She was having trouble eating," said her mother, Nikki, 23. "She kept spitting up." Doctors prescribed a change of formulas and Prevacid, a remedy for gastroesophageal reflux. And they advised the couple to slow down her feedings.

The couple, who grew up in Maryland, also noticed that Marisa's eyes would often roll upward and stay that way. Soon the baby began to lose her ability to swallow. She was getting sick, and began to experience seizurelike episodes where her eyes would glaze over.

More trips to doctors and emergency rooms, and twice-weekly hospital stays eventually led the Easterlys, in October 2009, to the University of Maryland Medical Center in Baltimore. Joel stayed by her side through two months of hospitalization there, and another month at the Mount Washington Pediatric Hospital. Eventually, doctors came around to their diagnosis: AADC.

AADC stands for "Aromatic L-Amino Acid Decarboxylase Deficiency." That means its victims can't make an enzyme needed to manufacture several neurotransmitters — chemicals critical to the conduction of impulses throughout the nervous system. Tests revealed Marisa's body makes no dopamine and very little serotonin.

Such deficiencies affect both voluntary movements and involuntary functions such as heartbeat, digestion, temperature regulation and more.

AADC is one of perhaps 10 similar genetic diseases that affect the production of neurotransmitters.

"Most are extremely rare," said Dr. Phillip I. Pearl, a pediatric neurologist at Children's National Medical Center in Washington who specializes in these illnesses.

"I'm sure there are that many [additional AADC cases] that have been diagnosed,but haven't been published," he said. "My guess is there are something like 50 to 100 cases worldwide."

Pearl has seen only about 10 AADC patients since he became involved with the disease in 1993. Most he met at meetings sponsored by support groups. He has had just two patients of his own, including Marisa and a boy, now 5. Pearl got his third with a new diagnosis on April 6.

In newborns, AADC is often misdiagnosed, Pearl said. "I have a case right now that, until he was 5 years of age, was coded cerebral palsy." His parents eventually saw a TV show about pediatric neurotransmitter diseases and asked for more tests, which revealed the child actually has AADC.

Neither Joel nor Nikki Easterly had ever heard of AADC before. Neither have most doctors. Marisa's doctors were baffled for months by her problems.

Routine lab work will not pick it up or provide a diagnosis. That requires a spinal tap and special handling of the spinal fluid as it is transported to one of the few labs in the world equipped to do the work, including just two in the U.S.

AADC is caused by a genetic defect inherited from both parents. When two such "carriers" find each other, there is a 25 percent chance that a child they bear will inherit copies from both parents, and with them the disease.

It is a tragic roll of the genetic dice. The defect causes a cascade of physical symptoms, with a complexity and severity that vary from one patient to the next.

"On the other hand, these children can have near-normal cognition" and intellectual development, Pearl said. "They may really understand what's going on around them. That's in a way part of the tragedy."

Now 2 years old, Marisa weighs no more than she did when she was diagnosed at 6 months. A sweet smile drifts across her face when her mother rocks her, and she can turn her head. But otherwise she moves very little. Her limbs are limp and atrophied. Her eyelids droop. She cannot hold her stuffed toys.

Nikki Easterly has a paper listing 22 symptoms that can appear in AADC children. Marisa has 20 of them.

"New stuff just kept happening," Nikki recalled. "The main thing was her not being able to eat." Marisa also has difficulty regulating her temperature; she is congested, has digestive problems, sleep disturbances, muscle spasms … Nikki's list goes on.

More hospitalizations followed as Marisa suffered one crisis after another.

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