WE reported a population association between a tryptophan hydroxylase (TPH) intron 7 polymorphism with suicidal behavior in Finnish alcoholic offenders and with cerebral spinal fluid 5-hydroxyindoleacetic acid concentration in impulsive offenders.1 Abbar et al2 found no association between a different TPH polymorphism and suicidal behavior in a clinically and ethnically divergent sample. Our TPH association was presented as a preliminary result requiring replication. However, the study by Abbar et al2 has little relevance to the validity of the association we observed. They used a different, unpublished TPH marker to genotype both women and men who were undergoing psychiatric care and who had a dissimilar and mixed diagnostic profile and a different ethnic background. Therefore, the assertion by Abbar et al of a "discrepancy" between their and our results has no basis.
The Ava II restriction fragment length poIymorphism used by Abbar et al2 is distinct from
Nielsen DA, Goldman D, Virkkunen M, Tokola R, Finland H, Rawlings R, Linnoila M. TPH Replication Study: Not!. Arch Gen Psychiatry. 1996;53(10):964–965. doi:10.1001/archpsyc.1996.01830100114015