• Advanced Paternal Age and Early Onset of Schizophrenia in Sporadic Cases: Not Confounded by Parental Polygenic Risk for Schizophrenia

      Wang, Shi-Heng; Hsiao, Po-Chang; Yeh, Ling-Ling; Liu, Chih-Min; Liu, Chen-Chung; Hwang, Tzung-Jeng; Hsieh, Ming H.; Chien, Yi-Ling; Lin, Yi-Ting; Huang, Yen-Tsung; et al. (Elsevier BV, 2019-07)
      BACKGROUND:Whether paternal age effect on schizophrenia is a causation or just an association due to con-founding by selection into late parenthood is still debated. We investigated the association between paternal age andearly onset of schizophrenia in offspring, controlling for both paternal and maternal predisposition to schizophrenia asempirically estimated using polygenic risk score (PRS) derived from the Psychiatric Genomics Consortium.METHODS:Among 2923 sporadic schizophrenia cases selected from the Schizophrenia Trio Genomic Research inTaiwan project, 1649 had parents’genotyping data. The relationships of paternal schizophrenia PRS to paternal ageatfirst birth (AFB) and of maternal schizophrenia PRS to maternal AFB were examined. A logistic regression model ofpatients’early onset of schizophrenia (#18 years old) on paternal age was conducted.RESULTS:Advanced paternal age over 20 years exhibited a trend of an increasing proportion of early onset ofschizophrenia (odds ratio per 10-year increase in paternal age = 1.28,p= .007) after adjusting for maternal age, sex,and age. Older paternal AFB also exhibited an increasing trend of paternal schizophrenia PRS. Additionally, aU-shaped relationship between maternal AFB and maternal schizophrenia PRS was observed. After adjusting forboth paternal and maternal schizophrenia PRS, the association of paternal age with patients’early onset ofschizophrenia remained (odds ratio = 1.29,p= .04).CONCLUSIONS:The association between paternal age and early onset of schizophrenia was not confounded byparental PRS for schizophrenia, which partially captures parental genetic vulnerability to schizophrenia. Ourfindingssupport an independent role of paternal age per se in increased risk of early onset of schizophrenia in offspring
    • The multidimensionality of schizotypy in nonpsychotic relatives of patients with schizophrenia and its applications in ordered subsets linkage analysis of schizophrenia

      Lien, Yin-Ju; Tsuang, Hui-Chun; Chiang, Abigail; Liu, Chih-Min; Hsieh, Ming H.; Hwang, Tzung-Jeng; Liu, Shi K.; Hsiao, Po-Chang; Faraone, Stephen V.; Tsuang, Ming T.; et al. (Wiley, 2009)
      This study aimed to examine the multidimensionality of schizotypy and validate the structure using ordered subset linkage analyses on information from both relatives’ schizotypy and probands’ schizophrenia symptoms. A total of 203 and 1,310 nonpsychotic first-degree relatives from simplex and multiplex schizophrenia families, respectively, were interviewed with the Diagnostic Interview for Genetic Studies, which contains a modified Structured Interview for Schizotypy. Using Mplus program with categorical factor indicators, a four-factor model (Negative Schizotypy, Positive Schizotypy, Interpersonal Sensitivity, and Social Isolation/Introversion) was extracted by exploratory factor analysis from relatives of simplex families and was confirmed in relatives of multiplex families. The validity of each factor was supported by distinct linkage findings resulting from ordered subset analysis based on different combinations of schizophrenia–schizotypy factors. Six chromosomal regions with significant increase in nonparametric linkage z score (NPL-Z) were found as follows: 15q21.1 (NPLZ ¼3.60) for Negative Schizophrenia–Negative Schizotypy, 10q22.3 (NPL-Z¼3.83) and 15q21.3 (NPL-Z¼3.36) for Negative Schizophrenia–Social Isolation/Introversion, 5q14.2 (NPL-Z¼3.20) and 11q23.3 (NPL-Z¼3.31) for Positive Schizophrenia–Positive Schizotypy, and 4q32.1 (NPL-Z¼3.31- ) for Positive Schizophrenia–Interpersonal Sensitivity. The greatest NPL-Z of 3.83 on 10q22.3 in the subset was significantly higher than the greatest one of 2.88 in the whole sample (empirical P-value¼0.04). We concluded that a consistent four-factor model of schizotypy could be derived in nonpsychotic relatives across families of patients with different genetic loadings in schizophrenia. Their differential relations to linkage signals have etiological implications and provide further evidence for their validity. 2009 Wiley-Liss, Inc.
    • RASD2, MYH9, and CACNG2 Genes at Chromosome 22q12 Associated with the Subgroup of Schizophrenia with Non-Deficit in Sustained Attention and Executive Function

      Liu, Yu-Li; Fann, Cathy Shen-Jang; Liu, Chih-Min; Chen, Wei J.; Wu, Jer-Yuarn; Hung, Shuen-Iu; Chen, Chun-Houh; Jou, Yuh-Shan; Liu, Shi-Kai; Hwang, Tzung-Jeng; et al. (Elsevier BV, 2008-11)
      Background: In a previous linkage study of schizophrenia that included Taiwanese samples, the marker D22S278 (22q12.3) was significantly linked to schizophrenia (p .001). Methods: We conducted fine mapping of the implicated genomic region, with 47 validated single nucleotide polymorphism (SNP) markers around 1 Mb of D22S278, in a Taiwanese sample of 218 pedigrees with at least 2 siblings affected with schizophrenia. We examined the association of these SNPs and their haplotypes with schizophrenia and with subgroups defined by the presence and absence of deficits in sustained attention as assessed by undegraded and degraded continuous performance tests (CPTs). We also examined subgroups defined by deficits in categories achieved in the Wisconsin Card Sort Test (WCST). Results: Three of five candidate vulnerability genes (RASD2, APOL5, MYH9, EIF3S7, and CACNG2), which had marginally significant associations with schizophrenia, had significant associations with schizophrenic patients who did not have deficits in sustained attention on the undegraded CPT (RASD2 gene SNP rs736212; p .0008 with single locus analysis) and the degraded CPT (MYH9 gene haplotype 1-1-1-1 of SNP rs3752463 - rs1557540 - rs713839 - rs739097; p .0059 with haplotype analysis). We also found a significant association for patients who showed no deficits in executive function as measured by categories achieved in the WCST (CACNG2 gene haplotype 2-1-1-1 of SNP rs2267360 - rs140526 - rs1883987 - rs916269; p .0163 with haplotype analysis). Conclusions: The genes RASD2, MYH9, and CACNG2 might be vulnerability genes for neuropsychologically defined subgroups of schizophrenic patients.