It's not that Isa Leah Cymrot-Wu didn't cry as an infant, it's just that there were no tears.

And that was only one unusual symptom the baby exhibited after she was born last July 20th. Specialists were baffled by the wide-faced child's bizarre constellation of symptoms; her fever spiked and sank seemingly without cause, her limbs looked floppy, she would gulp and swallow air.

Her parents, lesbian partners Barbara Cymrot and Dafna Wu, were terrified. Wu had chosen a sperm donor — a good friend from college — and the two had been carefully screened for medical problems.

But there is no way to screen for familial dysautonomia, or Riley-Day Syndrome as it is also called, a disease so rare there have been only 480 reported cases worldwide since 1970.

"I knew something was really wrong," says Wu, a labor and delivery nurse in San Francisco. But no doctor could explain the underweight baby's intermittent problems with breathing and digestion.

For the first 10 months of her life, the baby underwent a battery of tests that were all inconclusive. Doctors may not have suspected Wu, who is half Jewish and half Chinese, of carrying the rare genetic disorder that afflicts only Ashkenazic Jews.

More likely, doctors here had just never seen another case like it. Other than one reported case in San Jose, Isa is the only Bay Area baby to be born with the disease.

At 11 months old, she was incorrectly diagnosed to have spinal muscular atrophy, a condition that is usually fatal within three years.

"That was the worst day ever of my life," remembers Wu, sitting cross-legged on the floor in a sea of Tinker Toys with her now plump, smiley child. "I get upset just thinking about it."

The family embarked on the process of preparing for death. They consulted a pulmonologist on how to give the child morphine in the final stages of her illness, so she could die at home, where she was born. They began attending family grief counseling sessions with their 11-year-old daughter Ruby, who attends Brandeis Hillel Day School in San Francisco.

Just as they were learning to let her go, Isa started to thrive. She started to roll herself over — unusual for a child with a progressive neurological disorder.

"We thought, if she's leaving the planet, why is she starting to grow?" recalls Cymrot, an occupational therapist.

Finally, an opthamologist named Dr. Susan Day noticed the baby's eyes didn't tear and remembered learning about Riley-Day Syndrome only because the disease shares her name. She sent the family to the Dysautonomia Foundation in New York, where the baby was seen by the world's expert on the disease, Dr. Felicia Axelrod.

"She said it was a textbook case," says Wu.

Axelrod described what the family could expect. Dysautonomia causes abnormal nerve cell development, which means patients have impaired swallowing, awkward speech, a less than normal perception of pain and problems controlling their body temperature. Vomiting spells and breathing difficulties are also common, but intelligence isn't affected.

Another concern for parents of children with this disease is that dysautonomia prevents normal pain sensation, causing children to frequently break bones or burn themselves. They must be monitored constantly.

When doctors "said, `be careful when she runs around,' we said, `she's gonna run around?'" recalls Wu — who initially feared her daughter wouldn't live past the crawling stage.

Still, Cymrot says there will be "a great deal of medical management" required for the rest of the baby's life.

So far, Isa has had a gastronomy tube inserted that drips nutrients into her stomach during the night to provide extra calories and nutrition. She has also had a fundoplication, an operation that tightens the stomach to reduce the risk of aspiration from vomiting.

The child will have to travel back and forth to see Axelrod in New York at least twice a year.

Plane tickets for the family, medications, multiple physician and physical therapy appointments and formulas have drained the family's resources. What's more, Wu has had to cut back her hours at work to take care of her daughter, who requires not only "lots of stimulation and support" but a baby-sitter qualified to care for her.

In order to help the family cover expenses and make trips to the Dysautonomia Foundation, Jewish Family and Children's Services has set up a fund to receive donations of either money or frequent-flier miles.