---
title: Is a CLOCK gene variant linked to irregular periods? | Niyora
description: Yes, girls with the 3111T > C variant in the CLOCK gene had a clear increased risk of irregular menstrual cycles. This association held even after accounting
url: https://niyora.com/research/papers/association-between-the-clock-gene-3111-t-c-polymorphism-and-an-irregular-2015/
---

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- Is a CLOCK gene variant linked to irregular periods?

Survey study, 2015

# Is a CLOCK gene variant linked to irregular periods?

Yes, girls with the 3111T > C variant in the CLOCK gene had a clear increased risk of irregular menstrual cycles. This association held even after accounting for stress, anxiety, depression, and BMI.

 Early or limited evidence

197 postmenarchal adolescent girls from Seoul, Korea

## What they did

Cross-sectional study of 197 postmenarchal girls from two high schools in Seoul, Korea. All girls completed questionnaires about stress, anxiety, and depression and provided blood samples for DNA testing of two genes.

## What they found

Girls with the CLOCK 3111T > C gene variant showed a clear increased risk of irregular menstrual cycles, even after adjusting for age, stress, anxiety, depression, and BMI. The PER3 gene variant showed no clear association with irregular cycles.

## What it means for you

This gene variant may be an independent risk factor for irregular periods. However, this is a single study from Korea, and the association shown doesn't prove the gene causes the problem. The findings might not apply to all populations.

197

postmenarchal girls studied

2

gene variants tested

## About the study

Original title Association between the CLOCK gene 3111 T > C polymorphism and an irregular menstrual cycle in Korean adolescents Authors Kim KH, Kim Y, Ha J et al. Journal Journal of psychosomatic obstetrics and gynaecology Year 2015 Study design Survey study What was tested None - observational study Read the paper [doi.org/10.3109/0167482x.2015.1089229](https://doi.org/10.3109/0167482x.2015.1089229)

## Topics

[Sleep and insomnia](https://niyora.com/research/topics/symptom-sleep/)[Adolescents and young people](https://niyora.com/research/topics/life-area-adolescents/)

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