The dysbindin gene (DTNBP1) is associated with methamphetamine psychosis.

BACKGROUND: The dysbindin (DTNBP1 [dystrobrevin-binding protein 1]) gene has repeatedly been shown to be associated with schizophrenia across diverse populations. One study also showed that risk haplotypes were shared with a bipolar disorder subgroup with psychotic episodes, but not with all cases. DTNBP1 may confer susceptibility to psychotic symptoms in various psychiatric disorders besides schizophrenia. METHODS: Methamphetamine psychosis, the psychotic symptoms of which are close to those observed in schizophrenia, was investigated through a case (n = 197)-control (n = 243) association analyses of DTNBP1. RESULTS: DTNBP1 showed significant associations with methamphetamine psychosis at polymorphisms of P1635 (rs3213207, p = .00003) and SNPA (rs2619538, p = .049) and the three-locus haplotype of P1655 (rs2619539)-P1635-SNPA (permutation p = .0005). The C-A-A haplotype, which was identical to the protective haplotype previously reported for schizophrenia and psychotic bipolar disorders, was a protective factor (p = .0013, odds ratio [OR] = .62, 95% confidence interval [CI] .51-.77) for methamphetamine psychosis. The C-G-T haplotype was a risk for methamphetamine psychosis (p = .0012, OR = 14.9, 95% CI 3.5-64.2). CONCLUSIONS: Our genetic evidence suggests that DTNBP1 is involved in psychotic liability not only for schizophrenia but also for other psychotic disorders, including substance-induced psychosis.

The specific expression patterns of lactase, sucrase and calbindin-D9k in weaning rats are regulated at the transcriptional level.

During weaning, rat lactase-phlorizin hydrolase (LPH) expression decreased to the low levels found in adults, while sucrase-isomaltase (SI) sharply increased. Calbindin-D9k (CaBP) is specific to the intestine and expression peaked within a few days of weaning. The present study investigates whether these molecules are regulated at transcriptional or post-transcriptional levels and examines the effects of diet on regulation. At normal weaning on day 21, litters were separated from their dams and one group was fed with a standard laboratory diet (weaned (W) group). The other group received a diet containing lactose as the sole source of carbohydrate (lactose-fed (L) group). Mucosal cells were obtained from the proximal part of the rat small intestine and then the activity and concentration of LPH, SI and CaBP proteins and mRNAs were determined. Three parameters revealed the same changing patterns in LPH, SI and CaBP during development and there was significant (p<0.001) correlation between three parameters: LPH, r=0.97 for activity vs. protein, r=0.99 for activity vs. mRNA, r=0.96 for protein vs. mRNA, SI, r=0.99 for activity vs. protein, r=0.98 for activity vs. mRNA, r=0.96 for protein vs. mRNA, CaBP, r=0.94 for activity vs. protein, r=0.97 for activity vs. mRNA, r=0.95 for protein vs. mRNA. Expression of the three proteins did not differ between the L and W groups. Accordingly, it has been suggested that the expression of LPH, SI and CaBP during development is defined at the transcriptional level and dietary changes do not exert a primary effect on it.