| 1 | Psychiatr. Genet. 2012 Dec 22: 286-9 |
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| PMID | 22955840 |
| Title | Association of schizophrenia with the phenylthiocarbamide taste receptor haplotype on chromosome 7q. |
| Abstract | Phenylthiocarbamide (PTC) taste sensitivity is an inherited trait determined primarily by allelic variation of the taste-receptor gene TAS2R38 on chromosome 7q. Results of prior studies examining the ability to taste PTC in patients with schizophrenia have been mixed because of the difficulties in measuring PTC taste sensitivity behaviorally. In the current study, we examined the TAS2R38 genotypes of schizophrenia patients to determine whether the increased prevalence of nontasters in this patient population was indicative of a specific genetic association. Our a-priori hypothesis was that schizophrenia patients would show an increased prevalence of the nontaster phenotype compared with controls. The genotypes of two nonsynonymous coding single-nucleotide polymorphisms in TAS2R38 were assayed for 176 schizophrenia patients and 229 healthy control individuals, and the two-allele haplotypes were estimated. There was an over-representation of the major PTC nontaster haplotype among patients of European descent, relative to control individuals of similar ancestry. Patients and controls of African ancestry did not differ. The PTC nontaster haplotype is a genetic marker that may be used to identify subsets of schizophrenia patients who potentially harbor vulnerability genes in this region of chromosome 7q. |
| SCZ Keywords | schizophrenia |
| 2 | Psychiatry Res 2012 Aug 199: 8-11 |
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| PMID | 22503356 |
| Title | Phenylthiocarbamide (PTC) perception in ultra-high risk for psychosis participants who develop schizophrenia: testing the evidence for an endophenotypic marker. |
| Abstract | Reports suggesting that schizophrenia participants are more likely to be phenylthiocarbamide (PTC) non-tasters when compared to controls have recently been controversial. If supported, a genetic-based phenotypic variation in PTC taster status is implicated, suggesting a greater illness risk for those participants with recessive alleles for the TAS2R38 receptor. Should PTC insensitivity be a schizophrenia endophenotype, then it would be expected in follow-up of ultra high-risk for psychosis participants who later develop schizophrenia (UHR-S). UHR-S was hypothesised to show reduced PTC sensitivity compared to those who were previously at risk, but did not transition (UHR-NP). PTC perception was assessed in 219 UHR participants at long-term follow-up, of whom 53 had transitioned to psychosis (UHR-P) during the follow-up period. Fifteen of the 219 participants were diagnosed with schizophrenia. Seventy-eight had a family history of psychotic disorder. No differences in PTC taster status were found in UHR participants based upon transition to psychosis status, schizophrenia diagnosis, or family history of schizophrenia. This report indicates that schizophrenia development among UHR participants is not associated with PTC tasting deficits and fails to support previous findings that inability to detect the bitter taste of PTC is a schizophrenia endophenotype. |
| SCZ Keywords | schizophrenia |