F005 Tremor should not be underestimated: predominant motor symptom of intermediate phenotypes

<h3>Background</h3> Chorea is the predominant motor symptom in Huntington disease (in 90% of subjects), however few cases of other hyperkinetic movement (dystonia and tics) and ataxia have been reported also as initial and isolated symptoms, and without a clear correlation with CAG repeats number. Intermediate alleles (IA), that are in the range of 27 to 35 CAG repeats, are considered genetically unstable and there are some reported cases of subjects with IA and clinical Huntington Disease (HD) signs. <h3>Case History</h3> We present the case of two women first cousins currently 75 and 67 years old, who presented with tremor at the age of 74 and 54 respectively. The first patient manifested since young age psychiatric disorder characterized by thoughts of death (self- and other- harmful) and anxiety, and memory deficits in old age. Second patient developed walking ataxia with tendency to fall backwards and clozapine-responsive anxiety syndrome. Cerebral radiological investigations (brain MRI and 123I-Ioflupano DATScan) did not highlight any relevant anomalies. Known genetic and acquired causes for ataxia and tremor were excluded. Gene analysis for huntingtin gene showed the presence of 35 CAG repeats in both patients. During follow up, they did not experience any other hyperkinetic symptoms. <h3>Conclusions</h3> In the cases of the family reported, we underline how tremor is a possible motor presentation symptom in patients carrying intermediate alleles.