Objective: The aim of this study was to identify the genetic underlier of individuals presenting with chorea, allowing for the diagnosis of these patients, and contributing to the research on individuals from under-represented backgrounds. Strives in research in these countries will help to propagate better facilities and funding, which is vital.

Background: Dans les pays tropicaux à revenu intermédiaire inférieur, les tests génétiques de la maladie de Huntington (HD), de la chorée et de la maladie de Huntington de type 2 (HDL2) sont difficiles à mettre en place en raison de l’absence de laboratoire de biologie moléculaire. En effet, les ressources et le financement limités en Guinée constituent un problème majeur

Method: This is a study of cases reported from families in Guinea over a three-year period.  We included all patients presenting with neurological or psychiatric manifestations, and with a family history; and were assessed in relation to the criteria established by the UHDRS. Saliva samples were obtained with written consent of the participants, and DNA was extracted at the UCL Queen Square Institute of Neurology. PCR and subsequent DNA fragment analysis of the PCR products was used to identify the number of CAG/CTG repeats in the Huntingtin (HTT) gene and Junctophilin-3 (JPH3) gene. Alleles identified to have repeat sizes ≥36, for HTT, and ≥40, for JPH3 were considered pathogenic.

Results: In total, 15 patients, all presenting with chorea, were first tested for Huntington’s Disease, which was found to be negative for all individuals. The repeat sizes ranged from 15 to 26 repeats, with the majority of individuals (67%) having a repeat size fewer than 20. Next, we tested for pathogenically expanded repeats in JPH3. However, no individuals were found to carry the pathogenic expansion. The repeat sizes ranged from 13 to 28 repeats, with the majority (67%) of individuals having a repeat size <20. Therefore, it can be confirmed that there are no individuals in this cohort that have HD or HDL2.

Conclusion: This study shows the benefits of genetic testing for managing HD, chorea and HDL2 in a resource-limited environment. All individuals have chorea, yet they are negative for Huntington’s and HDL2, both of which have been seen to be prevalent in African populations.

References: [1], Claudia Cagnoli,* Alessandro Brussino,* Cecilia Mancini. Spinocerebellar Ataxia Tethering PCR A Rapid Genetic Test for the Diagnosis of Spinocerebellar Ataxia Types 1, 2, 3, 6, and 7 by PCR and Capillary Electrophoresis. The Journal of Molecular Diagnostics, Vol. 20, No. 3, May 2018,
[2], Krause A, Mitchell C, Essop F, Tager S, Temlett J, Stevanin G, et al. Junctophilin 3 (JPH3) expansion mutations caus- ing Huntington disease like 2 (HDL2) are common in South African patients with African ancestry and a Huntington dis- ease phenotype. Am J Med Genet B Neuropsychiatr Genet. 2015; 168 (7): 573-585. doi:10.1002/ajmg.b.32332,

[3], Coulibaly T, Karambe M, Guinto CO, Traore M. Huntington’s disease confirmed by genetic testing in three Malian families. Mov Disord 2012; 27(Suppl.1): 171

« Back to 2024 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/challenges-of-huntingtons-disease-and-chorea-in-guinea-the-benefits-of-genetic-testing-in-tropical-environments/