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A San Francisco toddler with a rare genetic disorder that afflicts only Ashkenazic Jews died this week at nearly 3-1/2 years old.

Isa Leah Cymrot-Wu died after an ear infection led to a string of complications related to her disease, familial dysautonomia.

"She's like a comet that flew through the sky and our lives," said her mother, Dafna Wu, who co-parented the child with partner Barbara Cymrot. "She just shone so brightly. She beamed."

In March of last year, the Bulletin ran a story about the young girl's odyssey. Jewish Family and Children's Services had started a fund to help her parents defray the significant medical costs involved with their child's treatment, which required trips to New York to see an expert on the disease.

Familial dysautonomia, or Riley-Day Syndrome, is so rare that only 480 cases worldwide have been reported since 1970. Other than one reported case in San Jose, young Cymrot-Wu was believed to be the only Bay Area baby with the illness.

Born on July 20, 1994, Cymrot-Wu exhibited a bizarre array of symptoms almost from the start. Fevers rose and fell without obvious cause. Her limbs appeared floppy. She would gulp and swallow air. She couldn't produce tears. For the first 10 months of her life, she underwent a battery of tests to try and pinpoint the symptoms; all proved inconclusive.

Wu, who carried the child and who is half Jewish and half Chinese, had been carefully screened for medical problems, as had the sperm donor, a close friend of Wu's from college. Unfortunately, there is no way to screen for Riley-Day.

At 11 months, the child was incorrectly diagnosed with spinal muscular atrophy, a condition that generally proves fatal within the first several years of life. Filled with sorrow, her parents prepared themselves for their baby's death, even attending counseling sessions with their 12-year-old daughter, Ruby, a seventh-grade student at Brandeis Hillel Day School in San Francisco.

Then, remarkably, the infant started to improve.

She rolled over, an unexpected development for a child with a progressive neurological disorder. Soon after, an ophthalmologist noticed the baby's eyes did not produce tears. She remembered that as being a symptom of Riley-Day Syndrome and sent the family to the Dysautonomia Foundation in New York. A doctor there gave a conclusive diagnosis and told the family what to expect in the future.

Intellectual capacity is not affected, but many other areas are.

Since the disease prevents sufferers from feeling normal pain sensations, children often break bones and bruise themselves. Vomiting spells and breathing troubles are common.

The young Cymrot-Wu, in fact, underwent fundoplication, an operation that tightens the stomach to reduce the risk of aspiration from vomiting. In the end, aspiration contributed to her death, leading to respiratory distress.

Wu said that despite her daughter's medical trials, the toddler burst with passion for everything from food to her moms, her sister and the ocean. "She was joyful and funny. She had a great sense of humor," Wu said. "We miss her terribly."

A memorial service for the child was held this morning at Sinai Memorial Chapel in San Francisco.

Cymrot-Wu is survived by her parents Barbara and Dafna and by Ruby, her sister. The family asks that contributions in Isa Leah's name be sent to the Dysautonomia Foundation, Inc., 20 East 46th St., 3rd floor, New York, NY 10017.