This is a very interesting study. Except for bradykinesia (slow movements), found in all four patients as compared to only 33 percent of the clinic's adult HD patients, symptoms were very similar between the juvenile and the adult group and there were no significant differences in MRI brain images.
Reading the detailed case reports, however, shows that each case presented and proceded very differently from the other and from adult HD. One girl presented with visual hallucinations at age 13. Aggressiveness was the next symptom, followed by chorea at age 15 and urinary incontinence at 16. One boy had tonic-clonic seizures at 3 months but developed normally until he was 8 years old when he presented with gait problems. Another boy began having problems with gait, speech, and lack of coordination at age 2. Although he had myotonic seizures at age 3, his EEG was still normal at that point. Another girl presented at age 4 with muscle contactions in her hands follow by gait problems at 6.
The full report can be found at: http://www.scielo.br/...
To describe the clinical presentation a group of patients with juvenile onset of Huntington disease.
All patients were interviewed following a structured clinical questioner. Patients were genotyped for the trinucleotide cytosine-adenine-guanine (CAG) repeat in the Huntington Disease gene. High resolution brain MRI was performed in all patients.
We identified 4 patients with juvenile onset of disease among 50 patients with Huntington disease followed prospectively in our Neurogenetics clinic. Age at onset varied from 3 to 13 years, there were 2 boys, and 3 patients had a paternal inheritance of the disease. Expanded Huntington disease allele sizes varied from 41 to 69 trinucleotide repeats. The early onset patients presented with rigidity, bradykinesia, dystonia, dysarthria, seizures and ataxia. MRI showed severe volume loss of caudate and putamen nuclei (p=0.001) and reduced cerebral and cerebellum volumes (p=0.01).
Eight percent of Huntington disease patients seen in our clinic had juvenile onset of the disease. They did not present with typical chorea as seen in adult onset Huntington disease. There was a predominance of rigidity and bradykinesia. Two other important clinical features were seizures and ataxia, which related with the imaging findings of early cortical atrophy and cerebellum volume loss.