Circadian Rhythm Gene Mutations in Psychiatric Disorders

Genetic Associations

Late-onset bipolar disorder type 1 has been associated with GRN mutations, which can evolve into behavioral variant frontotemporal dementia (bvFTD) 1
C9orf72 repeat expansion carriers may present with schizophrenia years before developing frontotemporal dementia 2
C9orf72 repeat expansions have been associated with psychiatric symptoms including bipolar disorder, obsessive-compulsive disorder, and schizophrenia 2
In C9orf72 mutation carriers, delusions and hallucinations (mostly auditory) are reported in 21-56% of cases 1
GRN mutations are associated with visual hallucinations and delusions in up to 25% of patients 4

Genetic testing for C9orf72 is recommended in late-onset psychiatric disorders with a first-degree relative with frontotemporal dementia (FTD) or amyotrophic lateral sclerosis (ALS) 4
Psychiatric symptoms may precede the classical presentation of neurodegenerative disorders by up to a decade in patients with circadian gene mutations 1
Severe psychotic symptoms may be a marker of an associated genetic abnormality in the circadian system 1
Understanding circadian timing is important for treatment efficacy, as medication responses may vary based on circadian phase 5
The relationship between circadian genes and psychiatric disorders is likely bidirectional - psychiatric disorders can disrupt circadian rhythms, and circadian disruptions can worsen psychiatric symptoms 3
Environmental factors and behaviors (irregular sleep-wake cycles, dark environments) can further disrupt circadian rhythms in those with psychiatric disorders 3
Circadian misalignment can adversely affect mental health, particularly mood regulation 3