Predictive testing for Huntington disease over 24 years: Evolution of the profile of the participants and analysis of symptoms

• Main Authors: Francis Ramond, Isabelle Quadrio, Laurence Le Vavasseur, Hélène Chaumet, Fabrice Boyer, Muriel Bost, Elisabeth Ollagnon‐Roman
• Format: Article
• Language: English
• Published: Wiley 2019-10-01
• Series: Molecular Genetics & Genomic Medicine
• Subjects: genetics; Huntington disease; neurogenetics; predictive testing; presymptomatic testing
• Online Access: https://doi.org/10.1002/mgg3.881

Abstract Background Huntington disease (HD) is a devastating neurodegenerative autosomal dominant genetic condition. Predictive testing (PT) is available through a defined protocol for at‐risk individuals. We analyzed the over‐24‐years evolution of practices regarding PT for HD in a single center. Methods We gathered data from the files of all individuals seeking PT for HD in Lyon, France, from 1994 to 2017. Results 448 out of 567 participants had exploitable data. Age at consultation dichotomized over 24 years toward an eightfold increase in individuals aged >55 (2/94 vs. 30/183; 2% to 16%; p < .0001) and twice as many individuals aged 18–20 (3/94 vs. 12/183; 3%–7%; p < .05). Motives for testing remained stable. The rate of withdrawal doubled over 24 years (9/94 vs. 38/183; 9%–21%; p < .02). Independently of the time period, less withdrawal was observed for married, accompanied, at 50% risk, and symptomatic individuals, and in those able to explicit the motives for testing or taking the test to inform their children. We also assessed the consistency between the presence of subtle symptoms compatible with HD found before the test by the team's neurologist, and the positivity of the molecular test. The concordance was 100% (17/17) for associated motor and cognitive signs, 87% (27/31) for isolated motor signs, and 70% (7/10) for isolated cognitive signs. Furthermore, 91% (20/22) of individuals who requested testing because they thought they had symptoms, were indeed found carriers. Conclusion This over‐24 years study underlines an increasing withdrawal from protocol and a dichotomization of participants’ age. We also show a strong concordance between symptoms perceived by the neurologist or by the patient, and the subsequent positivity of the predictive molecular test.