Farnoosh Ebrahimzadeh - Department of Internal Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Mehran Beiraghi Toosi - Department of Internal Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

We report an 8-year old girl with progressive movement disorder and worsening in school performances. Her grandfather was lost in 55 years old and her father had early dementia and lost in 32 years old. She was the first child of twin delivery without any problem and was good up to 6 years old. Her sister (the second twin) had developmental delay and worsened from 6 years old. In MRI she had only mild atrophy in head of caudate nucleus. According to history and physical examination we checked for Huntington disease that was strongly positive. Now in 13 years old, she and her sister are alive and under treatment of drugs and botulinum toxin. Huntington disease is a rare progressive autosomaldominant brain disorder (3 to 7 per 100,000 people) that causes abnormal movements, emotional problems, and loss of cognition. The most common form of Huntington disorder is adult form that starts in thirties or forties. In this form, early signs and symptoms include mainly irritability and depression. They may have mild abnormal movements, poor coordination, and also trouble in learning new information. The juvenile form begins in childhood or adolescence and is less common form. They mainly have movement disorder and sometimes mental and emotional problems and decline in school performance. Juvenile Huntington disease tends to progress more quickly than the adultonsetform; affected individuals usually live 10 to 15 years after signs and symptoms appear. Normally, the CAG segment (nucleotides) is repeated 10 to 35 times within the gene. In people with Huntington disease, the CAG segment is repeated 36 to more than 120 times.Patients with the adult-onset form, typically have 40 to 50 CAG repeats in the HTT gene, while children with the juvenile form, tend to have more than 60 CAG repeats (anticipation phenomenon).