Shedding Light on GLUT1 DS: Olivia’s Story

Olivia Tanner

She is a great advocate and spokesperson for herself and other people with disabilities.

Richard Morse, MD

Olivia Guziewicz was two-years-old when she was misdiagnosed with cerebral palsy (CP) and intractable—or uncontrollable—epilepsy while living in Connecticut. Thanks to her family’s move to Enfield, New Hampshire, five years later, she was correctly diagnosed with Glucose Transporter Type 1 Deficiency Syndrome (Glut1 DS) by Richard P. Morse, MD, Pediatric Neurology, Children's Hospital at Dartmouth-Hitchcock (CHaD). 

“Olivia was a shell of an individual when we moved here in 2004. You can’t fight the battle unless you know where it is. Dr. Morse saved her life. He listened to us, he listened to Olivia,” says her mother, Elizabeth Tanner. “He has really been an advocate for her and a partner for me.”

Understanding Glut1DS 

Glut1 DS is a rare genetic condition that makes it difficult for glucose, the brain’s main fuel, to transport energy across the blood-brain barrier due to impairment and decreased levels that affect cell function and don’t meet the energy demands of the brain. This results in seizures shortly after birth and developmental delays, as the brain cannot develop and function properly. According to the Glut1 Deficiency Foundation, approximately 90 percent of Glut1 DS patients experience seizures. Other common symptoms include complex movement disorders, speech and language impairments and intellectual disability, but symptoms and their severity vary widely among patients.

While the number of U.S. patients diagnosed with Glut1DS is only in the hundreds, the Foundation estimates it to be more common—likely occurring once in every 24,000 births. Many children are misdiagnosed because symptoms are similar to a variety of conditions, ranging from cerebral palsy and epilepsy, to autism and attention deficit disorder. Morse has only treated six or seven Glut1 DS patients during his 25 years of medical practice.    

Glut1 DS is also known as De Vivo Disease, as it was discovered by Daryl De Vivo, MD, pediatric neurologist, director emeritus (1979-2000) of the Child Neurology Service at Columbia University Irving Medical Center. In 1991, De Vivo published his findings describing the condition, and seven years later mutations in the SLC2A1 gene were identified as a cause. Along with improving the lives of patients, the Glut1 DS identification has advanced the understanding of mechanisms of epilepsy.

Early Glut1 DS identification is critical for preventing developmental and intellectual delays. Initially Glut1 DS was difficult to diagnose, as patients required spinal taps. Today, it is included in the gene panel blood test for epilepsy. 

Strict ketogenic diet=medicine

Luckily, the brain can burn fat instead of sugar. A diet based primarily in fats and very little carbohydrate, known as the Ketogenic Diet, puts the body into ketosis—providing an alternate way to use fuel. “It’s perfectly healthy but needs careful regulation. It is used to treat medically resistant epilepsy, but it’s the only treatment that works to treat Glut1 DS,” Morse says.

Tanner and her family had already recognized a correlation between what Olivia ate and how she operated: when she ate carbohydrates, her cognition, mobility and speech were worse. Without any knowledge of Glut1 DS, Tanner put Olivia on the Ketogenic Diet when she was five years old and observed a “night and day difference.” When Olivia was seven she started seeing Morse, who worked with De Vivo to confirm his hunch that she had Glut1 DS—not cerebral palsy and epilepsy.

Tanner and Olivia, now 23, maintain a schedule that requires eating carefully planned meals every two hours (six times daily) that are 3.5 times the amount of fat to protein and carbohydrates. Everything is measured exactly to the gram, and she eats 1,900 calories daily. Following the Ketogenic Diet keeps Olivia seizure-free, though she continues anti-seizure medication as a back-up.

A true success story

Olivia leads a very full life. A high school graduate, she reads at a 12th grade reading level; she volunteers at a local humane society and Full Circle Farm working with individuals with disabilities; runs; swims; and rides horses—despite having once been in a wheelchair—and works at BJ’s. She has a PathWays (a non-profit agency that serves people with disabilities) mentor who supports her daily activities, and they work on cooking, money management and staying active. She is also a supportive older sister to her siblings, Sophia and Zakery.             

“The team has had a major success with Olivia,” Morse says. “It’s largely to her mother’s credit. She had an amazing and impressive way of taking this on. Olivia’s outcome is phenomenal.”

Morse invited Olivia to participate in a Dartmouth-Hitchcock Neurology Megarounds prior to the COVID-19 pandemic. She enjoyed the questions posed by residents and providers who tried to pinpoint her diagnosis. “I don’t want a doctor to have someone like me and say she has cerebral palsy or autism, when that is not true,” Olivia explains. “Look for the unicorn, look for the rare.”

“She is a great advocate and spokesperson for herself and other people with disabilities,” Morse says. 

“Her will, drive and tenacity have really gotten her where she is today,” Tanner adds. “There is beauty and grace in this experience with her.” 

For more information about Glut1DS, visit the Glut1 Deficiency Foundation and the National Organization for Rare Disorders online.