Kathleen Edwards, the 9-year-old Michigan girl who made headlines when she was cyber-bullied for having Huntington's disease, has died, according to news reports.
Edwards' mother, Laura, died of the same disease in 2009, CBS News reported.
Kathleen was the subject of bullying by neighbor Jennifer Petkov, who the Daily Mail reports posted Facebook photos that show Kathleen's face over crossbones, and Laura's face lying next to the Grim Reaper. Petkov also drove around a truck with a coffin attached in front of Kathleen's home, CBS News reported.
CBS Detroit reported that Kathleen had pneumonia, which is especially dangerous for people with Huntington's disease.
Huntington's disease is a neurodegenerative disease, where nerve cells waste away in parts of the brain, according to the A.D.A.M. Medical Encyclopedia. It's caused by a genetic defect, where a section of DNA repeat many more times than it is supposed to.
A.D.A.M. reported how family history of the disease plays into symptoms:
As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the greater your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages.
Huntington's disease most often begins in the 30s and 40s, the Mayo Clinic reported, but sometimes people younger than age 20 can develop the disease.
Symptoms are wide-ranging, from movement problems -- muscle rigidity, problems swallowing, involuntary jerking and contracting of muscles and abnormal eye movements -- to cognitive problems -- slowness, problems learning, decreased impulse control, problems starting conversations and clumsiness, according to the Mayo Clinic.
The disease can also lead to depression, obsessive-compulsive disorder, bipolar disorder, mania, as well as other mood disturbances like anxiety, irritability and apathy, the Mayo Clinic reported.
For kids, the symptoms may be different from those in adults -- kids may experience seizures and tremors, loss of previously learned skills, problems with fine-motor skills (like handwriting) and behavioral problems, according to the Mayo Clinic.
Unfortunately, there is no cure for Huntington's disease, according to the National Institutes of Health. The disease is hereditary, with a person having a 50-percent chance of having it if a parent has it, too.
Diagnosis of the disease depends on outward signs -- like having abnormal movements or reflexes, dementia, poor speech or having a wide walk -- and can also be determined by brain imaging tests, according to the A.D.A.M. Medical Encyclopedia. There is no cure for the disease, but there are medications people can take for symptoms.
According to WeMove.org, an information site for movement disorders, Huntington's disease gets worse over time, and can lead to the inability to walk, talk and care for oneself. Complications include infection, choking, falls, heart failure and aspiration pneumonia (when foreign particles enter the lungs and cause inflammation).