Lack of association between MAGEL2 and schizophrenia and mood disorders in the Japanese population

A genetic locus for paranoia

The psychological effects of brain-expressed imprinted genes in humans are virtually unknown. Prader-Willi syndrome (PWS) is a neurogenetic condition mediated by genomic imprinting, which involves high rates of psychosis characterized by hallucinations and paranoia, as well as autism. Altered expression of two brain-expressed imprinted genes, MAGEL2 and NDN, mediates a suite of PWS-related phenotypes, including behaviour, in mice. We phenotyped a large population of typical individuals for schizophrenia-spectrum and autism-spectrum traits, and genotyped them for the single-nucleotide polymorphism rs850807, which is putatively functional and linked with MAGEL2 and NDN Genetic variation in rs850807 was strongly and exclusively associated with the ideas of reference subscale of the schizophrenia spectrum, which is best typified as paranoia. These findings provide a single-locus genetic model for analysing the neurological and psychological bases of paranoid thinking, and implicate imprinted genes, and genomic conflicts, in human mentalistic thought.

Possible association between ubiquitin-specific peptidase 46 gene and major depressive disorders in the Japanese population

BACKGROUND

Several investigations have reported that abnormalities in circadian rhythms might be related to the pathophysiology of major depressive disorder (MDD) and the therapeutic response to selective serotonin reuptake inhibitors (SSRIs). Recently, ubiquitin-specific peptidase 46 (USP46), a new molecule related to the circadian clock system, has been described. We conducted a case control study between seven tagging SNPs (rs10517263, rs17675844, rs6554557, rs12646800, rs2244291, rs10034164, rs346005) in the USP46 gene, MDD, and the SSRI therapeutic response in MDD in the Japanese population.

METHOD

We recruited 432 MDD patients (202 males and 230 females) and 792 healthy controls (319 males and 473 females). Two hundred sixty-one of 432 MDD patients were treated with SSRIs (fluvoxamine, sertraline or paroxetine).

RESULT

We detected an association between the USP46 gene and MDD in a haplotype analysis (rs2244291-rs10034164-rs346005 and rs12646800-rs2244291-rs10034164-rs346005). However, we did not find any association between the USP46 gene and SSRI response or remission in MDD in the Japanese population.

LIMITATIONS

A replication study using larger samples may be required for conclusive results, since our sample size was small.

CONCLUSIONS

Our results suggest that the USP46 gene might play a role in the pathophysiology of MDD in the Japanese population.