Objective: A region at chromosome 22q11.21 has been reported to potentially harbor a candidate gene for schizophrenia, ZDHHC8 (zinc finger, DHHC domain containing 8; also annotated as KIAA1292) in a number of studies. This finding has been replicated in Han Chinese, but not in other ethnicity-specific studies. For further support from within the Han Chinese ethnic group, we selected two single nucleotide polymorphisms (SNP) located at the distal 5'-end (rs1633445; intron 10 of HpaII tiny fragments locus 9C, HTF9C) and the intron 4 (rs175174) of ZDHHC8 gene to test if these were associated with schizophrenia in a study sample of Taiwan.
Methods: A total of 218 schizophrenia families with at least two affected siblings participated in this study. These two SNPs were genotyped using matrix-assisted laser desorption/localization ionization time of flight (MALDI-TOF) mass spectrometry.
Results: Significant associations with schizophrenia were not shown from these two SNPs. After stratifying schizophrenia according to the deficit and the nondeficit of sustained attention assessed by the Continuous Performance Test, the rs1633445 showed significant association with schizophrenia in the presence of a deficit in sustained attention (P<0.04).
Conclusion: SNP rs1633445 of the HTF9C gene may be associated with a deficit in sustained attention within schizophrenia, in a Taiwanese cohort. The deficit of sustained attention may be an endophenotype of schizophrenia, and warrants further study.