PREDICTORS OF DIAGNOSIS IN HUNTINGTON’S DISEASE
The disease first described by George Huntigton is caused by degeneration of neurons in the basal ganglia followed by cortical regions, leading clinically to involuntary movements (chorea), psychiatric symptoms and dementia. Nearly 90% of Huntigton’s Disease (HD) cases are hereditary and are transmitted in an autosomal dominant fashion. The other 10% are considered de novo.
The genetic locus underlying HD was originally mapped to chromosome 4q16 solely via the genetic analyses of DNA variants. Ten years later the gene responsible for HD was identified as encoding a 350 kDA protein (huntingtin) and containing a poly-CAG repeats in exon 1.
Subtle objective signs and subjective symptoms of HD are often present before the neurologic disease is clinically manifest, Langbehn, Paulsen & Huntington Study Group examined the prognostic significance of these early clinical clues (Langbehn, Paulsen & Huntington Study Group, Predictors of diagnosis in Huntington disease. Neurology 68, 1710-1717, 2007).
Authors analysed longitudinal data from 218 at-risk but healthy participants in the Huntington Study Group database who had either normal motor examination results or minimal soft motor signs at first observation.
As the researchers state in their abstract, findings demonstrate that neuropsychological performance and both the clinician rating and the patient subjective perception of motor difficulties contribute to a prediction of HD diagnosis. These findings may have implication for prognostic assessment of persons at risk and eventually assist with early interventions.