Soon, 3-year-old Tess Sullivan won’t be able to chew or swallow, and she will likely die between the ages of five and 10 due to a rare genetic disorder, the BBC reported.

Tess has Alexander disease, a terminal degenerative brain disorder that primarily affects children, and usually causes death within 10 years of the first symptoms.

The toddler, from Huncoat, England, was healthy at birth, but was diagnosed in December 2009 after showing some of the common symptoms, including epileptic seizures and slow development. She had surgery to remove parts of her skull after doctors discovered pressure to her brain.

Tess has the infantile form of the rare disease, which takes hold in the first two years of life and is the most common.

The juvenile form usually begins between the ages of four and 10. Adult onset Alexander Disease is the most rare and symptoms resemble those of Parkinson’s disease or multiple sclerosis, according to the National Institute of Neurological Disorders and Stroke website.

Tess will gradually lose her mobility, eyesight and the ability to chew and swallow.

“The biggest fear for us is, is she going to suffer? But we are of the mindset to take each day as it comes and have things to look forward to,” said Helen Sullivan, Tess’ mother.

Click here to read more from the BBC.