Send to

Choose Destination
Sleep. 1998 Sep 15;21(6):569-76.

A CLOCK polymorphism associated with human diurnal preference.

Author information

Department of Psychiatry and Behavioral Sciences, Stanford University Sleep Disorders Center, Palo Alto, Calif., USA.


A single nucleotide polymorphism located in the 3' flanking region of the human CLOCK gene was investigated as a predictor of diurnal preference in a population-based random sample of 410 normal adults. Morningness-eveningness preferences were determined using the 19-item Home-Ostberg questionnaire. Subjects carrying one of the two CLOCK alleles, 3111C, had a significantly lower mean Horne-Ostberg score. The distribution of scores was clearly shifted toward eveningness for these subjects. The score difference was independent of age, sex and ethnic heritage, thus making population stratification effects unlikely to explain this difference. These subjects had a substantial 10- to 44-minute delay in preferred timing for activity or sleep episodes. We suggest that the identified polymorphism or another tightly linked polymorphism within the CLOCK gene or its regulatory elements may be responsible for the finding.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center