PTK7 and panic disorder: Particularly, we detected that G/G genotype and G allele were less frequent in females with pure PD as compared to control females (p = 0.01 and p = 0.02, respectively), indicating a possible gender-specific effect of rs1386494 variants in pure phenotype of PD (Maron et al. 2007) In order to further clarify the involvement of this SNP in PD, we recently examined its effect on the vulnerability to CCK-4-induced panic attacks in 47 male and 63 female healthy subjects (Tõru et al. unpublished).