Huntington's disease in Turkey: genetic counseling, clinical features, and outcome

Abstract

Objective: This study aims to report the data of genetic counseling and to identify the clinical features of Turkish Huntington's disease (HD) patients and to investigate its possible relationship with genetic data.Method: A regular weekly outpatient clinic has been held routinely since January 2018. Patients and their referred relatives have been evaluated regarding clinical features and genetic counseling. The database of our collaborative team was used for the study.Results: Total 141 individuals have been evaluated. Among 84 subjects genetic counseling was given, diagnosis of HD was confirmed genetically in 34 (42.0%) of individuals (25 were symptomatic-HD, 9 were presymptomatic-HD). Fifty-seven patients were previously diagnosed with HD. The mean age of onset was 42.4 (11.9) years. Chorea was mostly reported initial symptom. The mean CAG repeat number of the expanded allele was 44.1 (5.1) and correlated inversely with the age of onset (p < 0.001). During a 4.8 (3.1) year follow-up, 10% of the patients were deceased. At the last visit, over half of patients had all of the movement, behavioral and cognitive problems, and 41.6% of them had required 24-hr supervision appropriate (UHDRS-independence score 64.6 (24.4)). Paternal inheritance was related to higher CAG repeats, younger age of disease onset, and higher UHDRS-motor scores.Conclusion: HD in Turkey is a severe disabling disease affecting a younger adult population. Over half of patients had all of the movement, behavioral and cognitive problems. Genetic counseling gives the opportunity to diagnose subjects at the pre-symptomatic phase. A collaborative approach is rational in the management of HD.

Keywords: Huntington disease; Turkey; alleles; chorea; cognition; genetic counseling; paternal inheritance.