Peggy and Tom Hart's second son was born on a humid July day in 1988 in a routine birth at a Towson hospital.
The Bel Air couple took home their healthy 9 1/2 -pound infant, looking forward to all the joys they had experienced with their first son, Sean, who was 4.
Baby Patrick smiled, cooed and developed normally until March 1989 when he was suddenly stricken by spasms and seizures.
The 8-month-old was soon diagnosed with tuberous sclerosis complex (TSC), a little-understood genetic disease, that eventually ravaged his body with tumors.
The blond-haired child, weakened by steroids he had to take to control the seizures, died of cardiac arrest three weeks before his first birthday.
His parents sought solace in family and friends, who organized a benefit dance to raise funds for research of the disease, which can cause medical problems ranging from mental retardation to autism.
Today, the fifth annual Snow Ball will be held from 7 p.m. to midnight at Harford Mall. It is expected to attract about 750 guests and raise more than $17,000 for TSC research.
"I'd like to think Patrick is smiling at us and saying, 'Good job, Mom,' " Mrs. Hart said.
Five years ago, TSC was considered a rare disease, but today, with better diagnosis, it is projected that 1 in 5,000 to 6,000 babies will have the disease.
"It is now one of the most common genetic disorders in the world," said Barbara K. Witten, president of the Landover-based National Tuberous Sclerosis Association (NTSA), which has 10,000 active members.
The national association estimates that there are 45,000 to 50,000 cases of tuberous sclerosis in the United States and more than 1 million worldwide.
"We have identified 200 families in Maryland," Ms. Witten said, "But there could be many more that don't know about us."
There is a 50-50 chance that parents who are carriers will pass on tuberous sclerosis to their children, said Dr. Vicky Holets Whittemore, medical director of NTSA.
In other cases, a mutated gene could cause the disease, she said.
There is no simple test to determine if someone has the disease. Currently, patients who have exhibited symptoms such as seizures or kidney failure undergo magnetic resonance imaging (MRI) and CAT scan testing to find out if there are tumors on internal parts of the body.
The tumors, which are benign, eventually grow and damage healthy organs, Dr. Whittemore explained.
There also can be white patches visible on the skin, she said. "It's a mysterious disease, because it can involve so many different organs."
Mostly, it affects the kidneys, eyes, heart, brain, skin and, potentially, the lungs, Dr. Whittemore said.
Researchers don't know the cause of the disease, although they have narrowed it to two genes in the body, Dr. Whittemore said.
Last month, a major breakthrough was made that could eventually lead to easier testing. One of two TSC genes was identified, representing the first step to solving a 100-year-old puzzle.
"This is the day we've been waiting for," Dr. Whittemore said. "The new findings will eventually lead to the development of appropriate therapies for those with this devastating disease."
The gene was found by researchers in Britain and the Netherlands, who published their study in the December issue of the scientific journal Cell. The search for the other gene continues, Dr. Whittemore said.
The money raised by Harford's Snow Ball is a large chunk of the $170,000 that goes into worldwide research of the disease, said Ms. Witten, the association director. This year's funds will be used to support one of the researchers working on the still elusive gene, she said.
After Patrick's death, the Harts, including their son, Sean, underwent extensive testing at Duke University. So far, there are no indications that they have the disease.
But it is a tricky disorder that can manifest itself at any time, even later in life, Dr. Whittemore said, citing the case of a 37-year-old woman who recently found out she had TSC.
Mrs. Hart knows this well. "Some people can have it but not be affected at all," she said.
The family soon had to face another grave period in their lives when Mrs. Hart became pregnant again. "It was a leap of faith," she said. "We said, 'OK, we're willing to take this child no matter what.' "
Their daughter, Adele, was born 1 1/2 years ago and, after testing, shows no signs of the disease -- and on a recent morning was bounding around her parents' living room.
"We were thrilled [about the birth]," said Patti Di Rito, a friend who had approached Mrs. Hart about the original fund-raiser five years ago.
"When Peggy lost Patrick, we all lost a baby," said the mother of five. "We wanted to do something."
Mrs. Di Rito has continued her work on the Snow Ball, this year gathering 99 prizes for a silent auction that is held during the dance.
She is among 19 committee members, headed by Chairwoman Lorraine Madden, who have been working since September on the black-tie-optional event. Tickets at $30 per person will be available at the door today.
Mrs. Di Rito and Mrs. Hart said they have to laugh about how the dance evolved.
"Peggy envisioned this affair at the mall," after several friends approached her about holding a benefit, Mrs. Di Rito said.
"We went along with her [idea for a dance], but we had really been thinking about something much simpler, like a bake sale or Tupperware party," she said.