We are extremely lucky to have a tremendous group of volunteers and professionals who give of their time and expertise to help the families in our community. Learn more about them below!

Dr. Elizabeth Barnhardt (WS & Autism) is a Developmental and Behavioral Pediatrician and Assistant Professor of Clinical Pediatrics at Nationwide Children's Hospital and The Ohio State University. She currently serves as a Co-Director of the Williams Syndrome Clinic at Nationwide and has a special interest in supporting children with both Williams syndrome and ASD and their families. She is also interested in medical education and is engaged with the Ohio State University College of Medicine as the Director of Competency in Interprofessional Collaboration and the Interprofessional Education Champion. She also has a passion for collaboration with primary care providers regarding the care of children with intellectual and developmental disabilities and is engaged in several projects related to developmental screening and primary care provider training to care for children with autism and other intellectual and developmental disabilities.

Denise Callen (4 & Under) is the Director of Walks for the WSA. She channels her passion for creative problem-solving and community engagement into meaningful events and fundraisers. With over a decade of experience owning and running a paint-your-own pottery studio and serving on the executive boards of CCSA and Mountaingate, she brings a blend of creativity, strategic thinking, and customer service.

Bianca Corozzo (Complex Communicator & Feeding Challenges) is a NYS Licensed Speech-Language Pathologist with over 23 years of experience in the field. In addition to her credentials in the field of Speech-Language Pathology, she holds a NYS School Building Leader Certification, demonstrating her commitment to educational leadership. Throughout her career, Bianca has held various roles, including Speech Therapist, Assistant Principal, Speech Evaluator, and Consultant. Her expertise lies in diagnosing and treating speech, language and behavioral challenges in both preschool and school-age children.

Christina Fitzgerald (Craft and Chat)

Sarah Giddings (Adventure Seekers) is the WSA's Interim Executive Director and Vice President of Programs and Services. She leads the development and execution of WSA programs and support services, which include a Family Support Network, scholarship program, conventions, camps, and programs to engage people with WS of all ages. She joined the WSA as staff part-time in 2020, then full time in 2021, but has been involved since her son Matthew was diagnosed in 2003 when he was 13 months old. She has served as one of our regional chair volunteers and as a member of our board of trustees. Her past professional positions have included leadership roles in learning and development, marketing, communications, sales, and events. Sarah attended Florida State University, is a Partners in Policymaking graduate, and served as a parent leader for other support organizations. She currently resides in Palm Bay, FL with sons Matthew (WS, born in 2002) and Connor.

Varun Indugula (Adult Siblings) is a student at UNC studying neuroscience and developmental disorders, who lives with his family, including his brother Prannoy (WS)

Jennifer Keeton (Teen/Tween) is a teen mom extraordinaire to 2 kiddos including Stella (WS). She also hosts the Starry-Eyed Podcast for the WSA.

Dr. Bonnie Klein-Tasman (WS & Autism) is a Professor in the Department of Psychology at the University of Wisconsin-Milwaukee. She has conducted research about the development of children with Williams syndrome about common behavior challenges, anxiety, personality, and also about overlaps in behaviors with autism spectrum disorders.

Joel Liestman (Only Child, Adventure Seekers, Teen/Tween) is the Director of Family Support for the WSA. He lives in Minnesota, with his wife, Jennifer, and their son, Bennett (WS). Before joining the WSA staff, he was the chairperson for the Upper Midwest region and a multifaceted volunteer coordinating Walk events, social media content, and even bridge lighting events to raise awareness of WS. In addition to his WSA duties, he serves on the Minnesota Governor's Council on Developmental Disabilities and the Disability Advisory Council (through the MN Secretary of State's office). He is a Partners in Policymaking™️ graduate. Most recently, he served as a Parent Support Navigator and Social Media Specialist with Family Voices of Minnesota. He also served as a Board Member for Partnership Resources, Inc., a Twin Cities-based service organization for adults with developmental disabilities. Joel has been a professional actor and singer for over 30 years. You can find more information about his advocacy and performances on joelliestman.com.

Rebecca Lyren, PhD (WS & Autism)

Carley Neilson (WS & Anxiety - Kids)

Julie Oglesbee (Grandparent) is a Family Support Specialist in Ohio and has been a long-time WSA volunteer at camps, national conventions, and regional WS awareness events. She is the grandmother to Grayson (WS) and a passionate supporter of the community.

Bill Palmer (Only Child) is the current President of the WSA Board of Trustees. He is a semi-retired engineer, and has worked for several nonprofit organizations in the building/infrastructure design and construction industry. He was executive director of two nonprofits and then spent 20 years as editorial director of a group of magazines and websites for construction contractors. Bill has also served on several volunteer boards, including the Williams Syndrome Association board of trustees, where he served and was president in the late 1990's during a critical growth period. During his term as president of his local library board, he helped raise several million dollars for a new library. Bill and his wife, Wynne live in Colorado with their 31-year-old daughter Autumn, who has WS.

Katie Raterink (WS & Anxiety - Adults)

Michelle Self (Transition to Adulthood, 'Think College' Programs) has worked for over 20 years with families of students with Williams syndrome to help them access an appropriate education and achieve their full potential. She started her career as a Materials Engineer in quality assurance, and then she opted for a career change and completed a PhD in Curriculum and Instruction with an emphasis in Special Education. She has worked as an adjunct professor at Bowling Green State University teaching junior-level students how to assess all types of learners, to write effective IEPs, and to assist in students’ transition from high school. At the same time, she regularly consulted with hundreds of families across the country.

Catherine Warden (Challenging Behavior) is the primary caregiver to her brother with Williams syndrome and a Special Needs Service Provider