Genetic Profiling of Huntington's Disease: Insights from CAG Repeat Analysis for Precision Diagnosis and Management.

Introduction: Huntington's disease is a monogenic neurodegenerative disease that is inherited in an autosomal dominant manner and is characterized by motor, psychiatric and cognitive symptoms that progress within 15 -20 years after diagnosis. In this study, we aimed to summarize our retrospectively compiled Huntington's disease diagnostic test results by correlating them with the patients' clinical findings. Methods: We conducted an analysis on a cohort of 88 individuals and evaluated their clinical symptoms. The research included the sample collections, isolation of DNA, the polymerase chain reaction (PCR) step, and capillary electrophoresis for fragment analysis. The results were assessed and the Cytosine-Adenine-Guanine (CAG) repetition count was computed. Results: The patients' CAG trinucleotide repeat (TNR) counts were determined. Individuals with a TNR of 39 and above were considered to have HD. Patients with increased clinical findings and pathogenic TNR counts were evaluated in terms of detailed phenotypic features and family history. The ages of the patients ranged from 24 to 85, with a mean age of 50.12. The study suggests that the expansion of genetic repeats may affect the age of onset of the disease. The most common initial symptoms were chorea and psychiatric symptoms. Most patients had a family history of the disease and the transmission from the father occurred earlier. Conclusion: It was emphasized that individuals with a TNR between 39 and above should be under the supervision of a physician. Prenatal diagnosis is recommended for those planning to have children. In addition, cases with a CAG trinucleotide repeat of 33 and 36 are recommended to inform the next generations about HD and to inform them about the possible effects in the future.