A point mutation at the calreticulin gene core promoter conserved sequence in a case of schizophrenia.

Exposure to atypical antipsychotic drugs such as valproate increases the expression of chaperones that assist in the folding of proteins in the endoplasmic reticulum (ER) including calreticulin, GRP78/BiP, GRP94, and PD1. This neuroprotective role may be involved in the pathophysiology of neuropsychiatric disorders such as schizophrenia and bipolar disorder. The 5'-flanking region of the human calreticulin gene was screened in 100 cases of schizophrenia by PCR/SSCA between -485 and +1 basepair (bp) relative to the transcription start site. A G > C point mutation was detected at -48 in a case of paranoid schizophrenia, which was not detected in 280 unrelated control subjects (560 chromosomes). This is the first report of mutation in relation with the calreticulin gene. The -48G > C mutation creates a CpG site at the core promoter region of the gene. The role of this mutation remains to be clarified in the pathophysiology of the disease.