Genetic link to chronic fatigue

Unexplained disabling fatigue in childhood is mainly due to genetic inheritance, a study of twins has revealed.

Chronic fatigue in young people can be disabling and is the main illness-related reason for long absences from school.

A genetic study of twins by researchers in Cardiff University's School of Medicine (Department of Psychological Medicine) found that although disabling fatigue and depression occur together, they have different genetic and environmental causes.

Participants were identified from the University's Cardiff Study of All Wales and North West of England twins. Parents of 1,468 twins and 930 older twin pairs took part in the study.

Analysis was undertaken for disabling fatigue of more than one week (short duration) and more than one month (prolonged).

The study led by Dr Tom Fowler with colleagues at Cardiff University and Professor Anne Farmer at the Institute of Psychiatry, London, found that 67% of the influences on short-duration fatigue in children and adolescents are genetic. The results suggest that prolonged fatigue is also linked to familial influences.

Dr Fowler, Department of Psychological Medicine said: "Our research found that the majority of genetic and environmental differences are specific to disabling fatigue and distinct from depression. This suggests the fatigue states in children should be considered as valid entities in their own right, and not as variants of depression."