Juvenile Huntington disease (JHD) amounts 10% of all Huntington disease (HD) cases and characterised by the manifests before 20, with a predominance akinesia and rigidity and progressive course of the disease. Although HD has an autosomal dominant pattern of inheritance, JHD in most cases is paternal inheritance with anticipation and the expansion of CAG trinucleotide repeats >60 in the IT15 gene located on chromosome 4p16.3; however, atypical cases exist, and maternal inheritance is possible. We present 6 (4 women and 2 men) JHD cases confirmed by DNA, where the number of CAG repeats varied from 60 till 66. All the patients had MRI which showed varying degrees of severity substitution hydrocephalus. Family nature of the disease was found in four cases (three maternal and one paternal inheritance). Two cases were not familial, but it is known that the mother did not have HD, and the father of one patient died at 46, and the other does not have information about his father. Four patients had akinetic-rigid form with onset between 12–19, three of them with cognitive decline. Two patients had a hyperkinetic form and cognitive decline. Diagnosis in 4 familial cases did not cause problems, although three of them had atypical maternal inheritance. Two isolated JHD cases were supposed 3 and 10 years after its onset that may indicate underestimation of JHD in practice. JHD probability should be kept in mind, even in cases with no family history, progressive akinetic-rigidy, choreic movements and cognitive decline DNA research on HD should be included.
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