Sequence, splice site and population frequency distribution analyses of the polymorphic human tryptophan hydroxylase intron 7.

A human tryptophan hydroxylase intron seven polymorphism previously associated with low CSF 5-HIAA and suicidal behavior was sequenced and characterized for its potential role in TPH pre-mRNA splicing. Two polymorphic sites were identified: A218C and A779C. The 779A allelic frequency in various populations ranged from 0.43 to 0.61 and was in strong linkage disequilibrium with the A218C site. A218C provides a site for restriction fragment length polymorphism analysis. TPH mRNA was reverse-transcribed and sequenced. No aberrant splice products from the 779A or 779G TPH genes were detected nor were any other polymorphic nucleotides found.