Clinical descriptions of juvenile-onset Huntington disease (HD) have been reported in at least 15 publications over the past 30 years, including the present series by Ribaï et al.1- 15 These descriptions range from case reports to series describing 112 patients, define juvenile-onset HD variably between 10 and 21 years, and draw samples from differing populations. With the exception of the Venezuelan cohort that contained both retrospective and prospective evaluations but did not focus on juvenile-onset cases, these series share one feature in common: they all represent retrospectively derived descriptions of individuals that are often obtained or reconstructed many years after onset of illness.
Biglan K, Shoulson I. Juvenile-Onset Huntington DiseaseA Matter of Perspective. Arch Neurol. 2007;64(6):783-784. doi:10.1001/archneur.64.6.783