Session Time: 1:45pm-3:15pm
Location: Exhibit Hall C
Objective: To compare AO and clinical presentation in Argentinean bi-allelic (BHD) patients, ie one mutated allele and one either intermediate (IA, 27-35 CAG repeats) or with reduced penetrance (RP, 36-39 CAG repeats), versus individuals with one full expanded heterozygous (FEH, ≥40 CAG repeats ) allele, and individuals with one RP with heterozygosity compound.to compare AO and clinical presentation in Argentinean bi-allelic (BHD) patients, ie one mutated allele and one either intermediate (IA, 27-35 CAG repeats) or with reduced penetrance (RP, 36-39 CAG repeats), versus individuals with one full expanded heterozygous (FEH, ≥40 CAG repeats ) allele, and individuals with one RP with heterozygosity compound.
Background: Patients homozygous for HD mutation are rare. Reports in the literature suggest a similar clinical manifestation and age of onset (AO) in heterozygous and homozygous patients. Only one study (Squitieri et al.2003) reported a more severe and rapid progression in homozygotes.
Methods: We retrospectively identified subjects with HD in our database from June 2003 to November 2016 and divided them in three groups: FEH and RP with heterozygous compound and BHD. AO was defined as the age at which severe behavioral, cognitive or motor abnormalities suggestive of HD were notified.
The study was approved by the Institutional Review Board.
Non parametric tests were used: Kruskal Wallis test for analysis of the three groups (FE, BHD and RP) with Wilcoxon test within groups with Bonferroni correction, Chi2 test for comparison between frequencies with a p≤0.05 considered significant. Analyses were carried out with G-Stat 2.0
Results: Of a total of 79 patients, 87.4% had FEH, 5 % had BHD with one RP, 7.6 % had a BHD with one IA.
There was no significant difference in clinical presentation between FEH and BHD (p=0.50 Fisher exact test). A significant difference in AO was observed between FEH and RP patients, the last with delayed AO (p=0.01, Wilcoxon test). There was no difference in AO between BHD and the other groups.
Conclusions: In our population BHD showed AO and clinical presentation similar to FEH and RP patients. We found a high BHD frequency in our cohort, thus disclosing a reservoir of low penetrance conditions and new mutations potentially contributing to a yet unknown HD prevalence.
To cite this abstract in AMA style:M. Cesarini, V. Parisi, G. Persi, J. Etcheverry, A. Sanguinetti, F. Squitieri, E. Gatto. A retrospective analysis of clinical forms and age of onset of biallelic Huntington disease patients from an Argentinean Center [abstract]. Mov Disord. 2017; 32 (suppl 2). https://www.mdsabstracts.org/abstract/a-retrospective-analysis-of-clinical-forms-and-age-of-onset-of-biallelic-huntington-disease-patients-from-an-argentinean-center/. Accessed December 1, 2023.
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