Jan. 23, 2013 -- Like many growing girls, Jenna Lyons was a self-perceived ugly duckling, but lately -- especially after J.Crew's colorful fashion line took center stage on the Obama girls at the inauguration this week -- she has emerged as a beautiful swan.
J.Crew's 44-year-old creative director said at Glamour's Women of the Year awards in November, "I know what it's like not to feel beautiful. ... I remember that feeling."
Stick-thin, with bold over-sized glasses and fashionably mismatched clothing, she has her own back story. Lyons was born with Bloch-Sulzberger syndrome or incontinentia pigmenti (IP), a genetic disorder that can cause skin scarring, loss of hair and malformed teeth. She has said she wears dentures.
In its most severe form, the genetic disorder can affect the central nervous system, causing seizures, learning disabilities and mental retardation, according to the Incontinentia Pigmenti International Foundation (IPIF), a nonprofit that supports research into the disorder.
Fortunately for Lyons, she has the milder form, which only discolors skin on the trunk. In some women it is so mild, it is never even diagnosed.
But IP can be deadly serious. Because it is an X-linked genetic mutation, it nearly always kills boys in utero. Males do not have a second X chromosome to overcompensate for the mutation, which attacks their immune systems.
In girls, there can be potential vision problems, including crossed eyes, cataracts or blindness.
Emily Batista, an 18-year-old who made a film about IP, "My Skin," at Reel Works Teen Filmmaking while in high school in Brooklyn, N.Y., said the psychological effects are just as traumatizing.
She has dark patches all over her body and missing teeth.
"IP was a struggle for me when I was younger," she said. "I got bullied a lot about my appearance. I never knew if I had a place in the world or if I was just that kid that would get picked on forever, but with a few good friends and as time went on I learned that we all mature and people really don't care about my appearance."
Like Lyons, Batista had dental surgery, but said, "the pain will be worth it in the end when I have the smile I dreamed of having as a kid."
Susanne Emmerich, founder and executive director of the IP foundation, told ABCNews.com that she hoped Lyons would also come out as a spokeswoman to bring awareness to the disorder.
Even if a milder case of IP is not life-threatening, women can be carriers and have a daughter with the devastating health consequences.
"I hear from a lot of young people who say they don't know anyone else with IP and they feel so isolated," said Emmerich, who wrote an email to Lyons asking her to get involved in the nonprofit foundation. "They need someone to identify with -- someone who deals with Michelle Obama, you couldn't get higher than that."
Lyons has addressed overcoming her earlier awkwardness in an interview with the New York Times last week. She said, "I am so not an insider, and that is O.K. I might feel like one in very particular moments. But I don't feel the same pressure I did when I was young to be part of the club. I'm not one of the cool kids, and that is totally fine."
Emmerich, a 75-year-old former fundraiser, said she founded IPIF in 1994 when her nephew's daughter was born with the disorder, but had been misdiagnosed.
"This was before there were genetic tests," she said. "She had little blisters that looked like herpes, which she didn't have. She was treated with medication for six months."
Babies with IP are sometimes born with a detached retina, which is correctable with laser surgery.
"She didn't have that, but if she had, it would have been a disaster," Emmerich said. "There can also be neurological implications."
Her grandniece, Gemma Stern, now 18 and a student at Tufts University, said she was "thrilled" when she learned that she had the disorder in common with fashion icon Lyons.
"It felt great to hear Jenna speak about her struggles growing up with IP because I can completely relate," she said.
Stern was self-conscious about a large bald spot on the top of her head, so when she was 10, she got a hair transplant. She has also undergone extensive dental work to correct her deformed teeth.
"Like Jenna, I have scars and discolored skin and have always been embarrassed when wearing shorts," she said. "Luckily, with age these scars have somewhat faded."
Like others, Stern was teased, but now in college, she said, "people are shocked when I tell them I have IP. ... I have gone to many doctors where I had to explain the disease to them."
Incontinentia Pigmenti Affects Girls Because It Kills Boys
IP is one of a group of diseases known as neurocutaneous disorders. In most cases, it is caused by mutations in an X-linked gene called NEMO (NF-kappaB essential modulator). Emmerich said that her foundation's international research arm helped identify the gene so that women who carry IP and who may not have symptoms can be tested.
Women with IP have a 50 percent chance of having a child with the disorder.
The mutation is carried on the X chromosome and is nearly always fatal in males, who have only one X. Females, with two X chromosomes, can compensate for the devastating symptoms of the disorder when one chromosome is normal.
In milder cases, skin abnormalities -- blue or brown wavy lines -- usually fade by adolescence and can disappear with age, according to the National Institutes of Health.
But there may be residual neurological effects, such a seizures, muscle spasms and mild paralysis that can be controlled with medication.
Dental malformations are common, such as missing or pegged shaped teeth -- in both baby and second teeth.
No one knows how prevalent the disorder is, according to Dr. Judith Willner, a retired geneticist from New York's Mt. Sinai Medical Center, who is head of the IP scientific advisory council.
"We used to think it was extremely rare until Suzanne Emmerich started her website and people have been contacting her from all over the world," Willner said. "It's much more frequent than previously thought. Sometimes it's so mild that people don't identify that they actually have it, and the symptoms can change over time."
The disorder's manifestations are "variable" in females.
"After the first couple of days (after birth), there is a blistering rash distributed on the trunk and limbs, but it spares the face," Willner said. "Gradually in most girls the rash flattens out and becomes more wart-like -- a raised brownish rash."
Eventually, the rash leaves only brown streaks behind.
"A woman may not even know she has the disorder," she said. More commonly, as in Lyons' case, IP involves the teeth and the hair. "They have patches of scalp with bald spots.
IP is "certainly compatible with a normal life," Willner said. "They can fix their hair and the rash is usually not disfiguring."
But the psychological effects, especially on looks-conscious girls, can be difficult.
"It's pretty terrible if a teen has bad teeth and the hair is not good -- it can be stigmatizing for girls," she said. "You can't put dental implants in a young child and have to wait until the second teeth come in."
Where the damaged X chromosomes are located -- in the brain, eyes or skin -- determine who will develop the severest symptoms like retardation or blindness, and who, like Jenna Lyons, will escape its devastation.
"It's a matter of luck and chance," said Willner. "It's totally random. You can be lucky or unlucky."