The short/long polymorphism in the serotonin transporter gene promoter is not associated with panic disorder in a Scandinavian sample

Several studies have reported an association between thes allele of the 5-HTT gene and anxiety-related person-ality traits in healthy individuals (Lesch et al., 1996;Mazzanti et al., 1998; Greenberg et al., 2000). In a case–control study, we selected 104 panic disorder researchparticipants (28 males and 76 females) from patients atthe Psychiatric Unit of Copenhagen University Hospital(Rigshospitalet). Diagnoses of panic anxiety disorderwere made according to the DSM-IV. All patients wereunrelated Scandinavians with a Caucasian genetic back-ground. The control group consisted of 108 healthy,unrelated individuals (30 men and 78 women). Compar-ison of the s and l allele frequencies between panicdisorder patients and controls revealed no differences.There were 86 s alleles (41%) and 122 l alleles (59%) inthe cases and 89 s alleles (41%) and 127 l alleles (59%) inthe controls. The genotype distribution revealed aslightly higher frequency of heterozygous panic disorderpatients than controls, but the difference was notsignificant. Stratification of the patient population intogender also failed to suggest any predominance of thes allele in either male or female panic disorder patients.We further examined whether the age-of-onset of panicdisorder was correlated to the genotype. To do so, wecalculated the mean age of the first episode of panicdisorder, but found no differences between homozygouss/s (27 years), homozygous l/l (28 years), or heterozygousl/s patients (27 years). The panic disorder groupcomprised patients with only panic disorder as well aspatients with comorbidity of phobia, either agoraphobia orsocial phobia. Patients with phobia had a trend towardsheterozygity. Allele frequencies revealed no differencesbetween either of the panic disorder subgroups and thecontrol group. Approximately half of the patients in thisstudy had a family history of either panic disorder orunipolar depression. This subgroup had a skeweddistribution of genotypes or alleles, but we failed todetect any significant differences between panic disorderpatients with or without a family history.