Child beating the odds against extremely rare genetic condition

By: Courtney Finafrock, Riley Children's Health videographer, cfinafrock@iuhealth.org

Scarlett Luanne Hoover was born on December 28, 2023, with an extremely rare genetic condition called KID syndrome. KID stands for keratitis-ichthyosis-deafness syndrome.

"Her variant of this condition is A88V," Matt Hoover, Scarlett's dad, explained. "From what we understand, this is what's considered the most severe variant."

Geneticist Dr. Erin Conboy explained that this genetic condition is caused by pathogenic or disease-causing variance in a gene that's in charge of making cells stick together well, and when that particular gene has a disease-causing variance in it, it doesn't allow that protein to be made well.

"That means that the skin itself does not fit together as well as it should, which is what causes kind of the worst part of the symptomatology, which is having thickened but breaking apart skin unfortunately," Dr. Conboy said.

While the smiley little girl suffers from wounds and bleeding across her whole body, her mom, Mariah Williamson, said Scarlett does not indicate she is in a great deal of pain.

"I think she's just mainly uncomfortable," Williamson said. "Just because of her skin, with her scratching, she itches all the time. Unfortunately, she can make herself bleed. Her nails they're not normal. They can be really thick. Sometimes they can be claw-like. So, they're hard to stay trimmed. It's really the skin on the palms of her hands that make her bleed because it's so thick."

Williamson works diligently to keep up on her daughter's skin care to avoid further discomfort.

"I lather her in Aquaphor," Williamson explained. "Her bandages that are covered up, we have a gentamicin ointment which is a broad-spectrum antibiotic. And then she has special wound dressings; It has silver in it to help with her wounds."

Dr. Conboy explained that KID syndrome is an autosomal recessive condition.

"That means that we all have two copies of this particular gene: GJB2," Dr. Conboy said. "People who have one copy that has a misspelling in it are fine and they're carriers of this condition. But if a mom and a dad have a child and they happen to pass on both of their misspelled copies of this gene, then the child has the condition. This is recessive, meaning the child needed to inherit both copies."

Dr. Conboy said KID syndrome would rarely, if ever, show up on an ultrasound. But certain genetic testing could detect it.

"There's pre-conception genetic testing." Dr. Conboy said. "There's also genetic testing that can be done in utero. From that perspective, we would recommend carrier screening for parents. Then that carrier screening can determine whether there's a risk for the child. So, if parents happen to be carriers for the same condition, then we talk about the risk to future pregnancies."

There are only 100 published cases of KID syndrome ever, so this condition is extremely rare. Scarlett's parents said that early on, doctors gave her a prognosis of one year or less.

"It's very surprising that she is still here," Williamson said. "They don't live past a year old with her variant with her syndrome, and she'll be three in December."

Dr. Conboy explained why she is always hesitant to provide families with a life expectancy number, especially when little is known about a certain condition.

"We rely on the literature and our personal experience about how kids will do over time," Dr. Conboy said. "And what I've learned, and my colleagues have learned, is that just because the literature says that life expectancy is a certain time frame, that doesn't mean that the child in front of you is going to have that same course. So, what I like to tell families is that life expectancy and how kids will do over time is really unpredictable, because they're just too many variables. They're genetic variables, environmental variables, and things that even we don't have an idea about right now. And so, I would never, in my experience, say never put a timeframe on morbidity, mortality, life expectancy; things are just too unpredictable for that future."

For now, Scarlett's parents try to live every day to the fullest. Scarlett provides them plenty of joy between her contagious laugh, funny facial expressions and her love of the Mickey Mouse Clubhouse.

"She's a very funny, outgoing little girl," Williamson said. She is still very much so just Mommy and Daddy's girl, though."