PT - JOURNAL ARTICLE AU - Sophie Tezenas du Montcel AU - Alexandra Durr AU - Maria Rakowicz AU - Lorenzo Nanetti AU - Perrine Charles AU - Anna Sulek AU - Caterina Mariotti AU - Rafal Rola AU - Ludger Schols AU - Peter Bauer AU - Isabelle Dufaure-Garé AU - Heike Jacobi AU - Sylvie Forlani AU - Tanja Schmitz-Hübsch AU - Alessandro Filla AU - Dagmar Timmann AU - Bart P van de Warrenburg AU - Cecila Marelli AU - Jun-Suk Kang AU - Paola Giunti AU - Arron Cook AU - Laszlo Baliko AU - Melegh Bela AU - Sylvia Boesch AU - Sandra Szymanski AU - José Berciano AU - Jon Infante AU - Katrin Buerk AU - Marcella Masciullo AU - Roberto Di Fabio AU - Chantal Depondt AU - Susanne Ratka AU - Giovanni Stevanin AU - Thomas Klockgether AU - Alexis Brice AU - Jean-Louis Golmard TI - Prediction of the age at onset in spinocerebellar ataxia type 1, 2, 3 and 6 AID - 10.1136/jmedgenet-2013-102200 DP - 2014 Jul 01 TA - Journal of Medical Genetics PG - 479--486 VI - 51 IP - 7 4099 - http://jmg.bmj.com/content/51/7/479.short 4100 - http://jmg.bmj.com/content/51/7/479.full SO - J Med Genet2014 Jul 01; 51 AB - Background The most common spinocerebellar ataxias (SCA)—SCA1, SCA2, SCA3, and SCA6—are caused by (CAG)n repeat expansion. While the number of repeats of the coding (CAG)n expansions is correlated with the age at onset, there are no appropriate models that include both affected and preclinical carriers allowing for the prediction of age at onset. Methods We combined data from two major European cohorts of SCA1, SCA2, SCA3, and SCA6 mutation carriers: 1187 affected individuals from the EUROSCA registry and 123 preclinical individuals from the RISCA cohort. For each SCA genotype, a regression model was fitted using a log-normal distribution for age at onset with the repeat length of the alleles as covariates. From these models, we calculated expected age at onset from birth and conditionally that this age is greater than the current age. Results For SCA2 and SCA3 genotypes, the expanded allele was a significant predictor of age at onset (−0.105±0.005 and −0.056±0.003) while for SCA1 and SCA6 genotypes both the size of the expanded and normal alleles were significant (expanded: −0.049±0.002 and −0.090±0.009, respectively; normal: +0.013±0.005 and −0.029±0.010, respectively). According to the model, we indicated the median values (90% critical region) and the expectancy (SD) of the predicted age at onset for each SCA genotype according to the CAG repeat size and current age. Conclusions These estimations can be valuable in clinical and research. However, results need to be confirmed in other independent cohorts and in future longitudinal studies. ClinicalTrials.gov, number NCT01037777 and NCT00136630 for the French patients.