Association of Variant rs4790904 in Protein Kinase C Alpha with Posttraumatic Stress Disorder in a U.S. Caucasian and African-American Veteran Sample

BACKGOUND: Posttraumatic stress sisorder (PTSD) is a complex anxiety disorder that can develop after traumatic event exposure. Genetic factors have been associated with PTSD risk. Recently a variant rs4790904 in the protein kinase C alpha (PRKCA) gene has been shown to be associated with PTSD risk. The objective of this study was to replicate this association in a sample of U.S. Afghanistan/Iraq era veterans. METHODS: The genotypes of rs4790904 were evaluated in all trauma-exposed veterans. The sample of U.S. veterans included 428 Caucasians and 533 African-Americans. The statistical analysis was conducted independently in the Caucasian and African-American subjects to evaluate the association with PTSD symptom clusters of B symptoms (re-experiencing), C symptoms (avoidance and numbing), D symptoms (hyperarousal), and with current PTSD diagnosis. RESULTS: The sample was comprised of 428 Caucasians (186 with current PTSD diagnosis, 242 trauma-exposed controls; median age, 35 years; 15% female) and 533 African-Americans (205 with current PTSD diagnosis, 328 trauma-exposed controls; median age, 41 years; 31% female). We observed a significant correlation between rs4790904 and all three PTSD symptom clusters in the Caucasian population, but no significant association with current PTSD diagnosis. However, these significant associations were with the G allele, rather than the A allele, that was previously reported by de Quervain. A significant association of this variant with current PTSD diagnosis (p=0.046) was detected in the African-American veterans. CONCLUSION: We confirmed the correlation between rs4790904 and all three PTSD symptom clusters in the Caucasian but not the African-American population. A significant association with a current diagnosis of PTSD was found in the African-American veterans.