In the Chinese Han population, the genotypic (P=0.038) and allelic (P=0.033) frequencies of the 3'-untranslated region (UTR) genetic variation of rs2844337 in patients were significantly decreased compared to that in controls; these frequencies were significantly associated with SCZ susceptibility in the additive model (P<sub>adj</sub>=0.032) and in the recessive model (P<sub>adj</sub>=0.031).
These results support that the (AGG)n > or = 15 alleles could be protective factors against schizophrenia and thus they suggest a possible involvement of GDNF gene in the genetic liability to illness.