A variable-number tandem repeat polymorphism in PER3 is not associated with chronotype in a population with self-reported sleep problems

We examined whether a variable-number tandem repeat (VNTR) polymorphism in the circadian clock gene PER3 was associated with subjective ratings of sleep and diurnal preference in a Romanian population with high levels of self-reported sleep problems. Individuals, self-reporting to their GP for sleep disturbances, completed a battery of validated scales that assess the presence of insomnia, sleep quality and diurnal preference and had their PER3 VNTR genotype determined. We found no significant differences in chronotype, sleep quality or other psychometric measures according to PER3 VNTR and conclude that diurnal preference or self-reported sleep measures are not associated with PER3 genotype in this population.