Johanna Sweet and her daughter Emma wearing a full protective hat with face shield
By Roanoke College News

Genetics students gain rare opportunity to learn about living with rare disease

Students in Dr. Marilee Ramesh’s Biology 380 Advanced Genetics class had an incredible opportunity to question and talk with the parent of a child with the especially rare genetic disease Xeroderma Pigmentosum (or XP) this spring. The parent they spoke to was another professor, Dr. Johanna Sweet, Associate Professor of Business Administration.  

XP, in layman’s terms, is an allergy to ultraviolet light where the patient’s body can’t repair any sun damage or even damaging UV rays from some light bulbs. XP is so rare that only about 200 people in the United States, including 80 children, have it.  

Sweet’s 7-year-old daughter, Emma, was diagnosed with XP five years ago. She is the only XP patient in Virginia. 

“It’s difficult to diagnose,” Dr. Ramesh, professor of biology, said, “and it’s a life-altering situation for the individual and the family to respond to the disease. It’s rare. I had only heard about it in textbooks.”  

“We have so many students going into health care, this gives them an opportunity to make the connection between the theory we’re learning in class and the personal challenges the patient must manage,” Ramesh said. “Johanna has been gracious spending her time with us. This is the third year we’ve done this event in my class.”  

“Hearing from the mother of a person living with XP has allowed me to understand more than just the science behind the disease,” said Attiya Daniels ‘22, a biology major. “As someone who wants to be in the health care field, Sweet’s story has allowed me to understand in-depth why compassion is important when caring for patients.” 

Ramesh said the class studies the genetic mutation present in XP patients and its connection with the DNA repair pathways in the class. Students learn about the molecular mechanisms and this opportunity helps illustrate how the disease would manifested in a patient. 

“We wanted to balance the understanding of the scientific impact with the personal impact XP has on the patient. Our students see how a real family lives with XP,” Ramesh said.  

“It was really inspiring to have the opportunity to hear Dr. Sweet speak about Emma’s story with Xeroderma Pigmentosum,” said Kavya Iyer ‘22, a biochemistry major. “XP is such a rare disease, it is important to increase research to study the disease, as well as promote outreach for further education.  I really enjoyed being able to make the connections from the classroom settings, understanding the types of mutations in DNA and how it ultimately translated into very rare diseases.”   

“My whole reason for doing this is whole person development,” Sweet said. “I want the students to not just see a disease but to recognize there’s a person behind the disease. And I try to raise awareness of XP.”  


Family life with XP

“It’s my ‘day to day’ but when I talk about it, I realize how different our lives are from other people. ”

Dr. Johanna Sweet, Associate Professor of Business Administration

Sweet said the experience was two hours of questions from the students. She speaks briefly to start, introduces the students to pictures of Emma and an overview of the disease. Then they ask questions.  

"The students were very engaged,” Sweet said. “They had very good questions thought-provoking questions that showed their critical thinking skills.” 

Basic questions included: How did Sweet know Emma had XP? What research is out there? How did COVID-19 impact her situation? What are other medical components that go with XP? Some questions were more about the family dynamics: How does Sweet’s son deal with XP? How do you live on a day-to-day basis? What are Sweet's fears?  

Sweet said she was emotional after the talk.  

“It’s my ‘day to day’ but when I talk about it, I realize how different our lives are from other people,” she said. 

Sweet’s family life is different from most. Emma has special gear she must wear anytime she goes outside in the daytime. She must wear a hat they call it “Emma’s fan hat,” because it has a fan inside to keep her cool two layers of clothing with long sleeves, and long pants as well as gloves. Windows must be tinted as well. Windows in Sweet’s home and car are tinted, as well as the windows in the rooms Emma uses at school and at church.  

The Sweet family life got even more complicated this past year when Sweet’s 9-year-old son was diagnosed with celiac disease. Now, the family must bring their own food (in addition to all of Emma’s gear) to many activities because he can’t have any gluten.  

Sweet said Emma is doing well, despite living with XP.  

“She’s a spunky child,” Sweet said with a smile. “Lots of spirit, very independent and she can be sassy.”  

“My job is to make sure she can do anything she wants to do, but we have to be creative in finding ways to make that happen,” Sweet said.  

But they do. Emma rides horses, goes to school, swims in the lake, plays basketball and plays on the playground with her friends. 

“Especially with rare diseases, there’s no financial incentive for pharmaceutical companies to come up with treatments,” Ramesh said. “It's the family members who are advocating, connecting and searching for support, more so than the communities we typically think about as doing research. This is a big challenge for someone dealing with a disease that’s rare.” 

Sweet is a dedicated advocate and stays on top of XP research herself. She keeps a Google Scholar Alert, so she’s notified when a new scholarly paper about XP is published. Recently, the research in her alert was about Emma. 

Because XP can cause cancer from sun exposure, Sweet was warned that Emma could develop skin cancer because of sun exposure before she was diagnosed. Early this year, Emma had a tumor removed from her scalp. The tumor was benign but a rare neurochristic hammertoma. Emma was the first XP patient to have one. Doctors asked for Sweet's permission to write a scholarly paper to inform other doctors. 

The class was “a truly enlightening experience,” Marrett Gilfus ‘22, biochemistry major, said. “My grandmother actually had some experience with the XP camp in New York where the children only go out at night. So while I knew of the condition, it's so extraordinarily rare that I still had never heard a story from anyone directly living with this condition.  This was truly an exceptional opportunity to understand, that while rare, these illnesses do touch the lives of people in our community.” 

If you are interested in more information on XP, please visit  

Johanna Sweet's family experience with XP

Dr. Johanna Sweet's daughter, Emma, was diagnosed with the very rare XP five years ago.