Maintenance of Chronic Fatigue Syndrome (CFS) in young CFS patients is associated with the 5-HTTLPR and SNP rs25531 A > G Genotype

Earlier studies have shown that genetic variability in the SLC6A4 gene encoding the serotonin
transporter (5-HTT) may be important for the re-uptake of serotonin (5-HT) in the central
nervous system. In the present study we investigated how the 5-HTT genotype i.e. the short
(S) versus long (L) 5-HTTLPR allele and the SNP rs25531 A > G affect the physical and
psychosocial functioning in patients with chronic fatigue syndrome (CFS). All 120 patients
were recruited from The Department of Paediatrics at Oslo University Hospital, Norway, a
national referral center for young CFS patients (12–18 years). Main outcomes were number
of steps per day obtained by an accelerometer and disability scored by the Functional Disability
Inventory (FDI). Patients with the 5-HTT SS or SLG genotype had a significantly lower
number of steps per day than patients with the 5-HTT LALG, SLA or LALA genotype. Patients
with the 5-HTT SS or SLG genotype also had a significantly higher FDI score than patients
with the 5-HTT LALG, SLA or LALA genotype. Thus, CFS patients with the 5-HTT SS or SLG
genotype had worse 30 weeks outcome than CFS patients with the 5-HTT LALG, SLA or
LALA genotype. The present study suggests that the 5-HTT [...]