Among various hypotheses suggested for schizophrenia (SZ) Pathogenesis, genetic factors are gradually supposed to play more significant roles. Amid these schizophrenia candidate genes, ATP-binding cassette transporter13 (ABCA 13) has recently received limelight as its expression has been found to be decreased in patients with SZ, as reported in a study by Lu Qian et al. published in the latest issue of Nature Research.
It is very well known that schizophrenia imposes a massive burden on individuals, their families, and healthcare providers. It is seen that the heritability of SZ is 60-80%. ABCA 13 is located on human chromosome 7p12.13. It is widely expressed in human brain areas, bone marrow, and other tissues. Disruption of ABCA-13 expression in the human hippocampus and frontal cortex have implicated aberrant lipid biology as a pathological pathway in mental illnesses. However, the functional role of ABCA13 at the level of gene expression and relationship to the severity of core psychotic symptom of SZ is still unknown.

Also Read:Chen J, Khan RAW, Wang M, He K, Wang Q, Li Z, Li W, Wen Z, Song Z, Shen J, Xu Y, Shi Y. Association between the variability of the ABCA13 gene and the risk of major depressive disorder and schizophrenia in the Han Chinese population. World J Biol Psychiatry. 2017 Oct;18(7):550-556. doi: 10.1080/15622975.2016.1245442.
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In this study, it was hypothesized that the patients with SZ have abnormal ABCA 13 expression and treatment with antipsychotic drugs results in the relief of psychotic symptoms and restoration of abnormal ABCA 13gene expression. It is the first study to explore mRNA expression level of ABCA 13 in peripheral blood by RT-qPCR in the Han Chinese population. Thirty-two drug naïve SZ patients were enrolled along with 48 healthy controls. Positive and Negative Symptom Scale (PANSS) was used to measure the psychotic symptoms of SZ patients at baseline and 12 weeks after the drug therapy.
The data was analyzed and it was found that: -
1. PANSS score at 12 weeks after drug therapy was significantly lower than the scores at baselines. - Mean ABCA 13 mRNA expression levels of SZ patients were significantly lower at both baseline and after 12 weeks of drug therapy compared to the healthy controls (figure).
2. However, the ABCA13 mRNA expression level increased after 12 weeks of antipsychiatric drug therapy than baseline.
3. Of the clinical symptoms measured, there was a negative association between ABCA13 mRNA relative expression levels and PANSS total scores at baseline. After 12 weeks of drug therapy, there was a negative association between ABCA13 mRNA relative expression and PANSS scores too.
To summarise, results showed that the ABCA13 expression levels in SZ patients are lower than those of healthy controls at baseline, and increased after 12 weeks of drug therapy. However, the ABCA13 expression levels are still lower than those of the healthy controls. The results also indicated that the ABCA13 mRNA expression level is of interest, and upon further studies, it could be used as a biomarker for SZ treatment outcomes.
Source: Nature research journal: Qian, L., Qin, Y., Chen, X. et al. ATP-binding cassette transporter 13 mRNA expression level in schizophrenia patients. Sci Rep 10, 21498 (2020). https://doi.org/10.1038/s41598-020-78530-9