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Certain birth factors associated with schizophrenia risk in patients with genetic condition

Researchers from Canada found that small gestational age and preterm birth significantly predicted the risk of developing schizophrenia in patients with 22q11.2 deletion syndrome, according to recent study results published in Genetics in Medicine.

“Low birth weight and preterm birth have been proposed as risk factors in schizophrenia in general, but past studies have not shown a large effect on risk,” Anne S. Bassett, MD, FRCPC, director of the Clinical Genetics Research Program at the Center for Addiction and Mental Health in Toronto, stated in a press release. “We've focused our lens on these risks in a small population with a specific genetic subtype of schizophrenia, where the connection between birth factors and risk of developing schizophrenia is noticeably stronger.”

Bassett and colleagues analyzed the birth weight and prematurity of 123 patients with 22q11.2 deletion syndrome. Patients were mean 32.7 years old, 45.5% of the population was male and 85.4% were of European ancestry. The researchers defined small gestational age (SGA) as being in less than the 3rd percentile for gender and gestational age, and preterm birth as being born at less than 37 weeks gestation.

Fifty-one patients in the study were diagnosed with schizophrenia and the remaining 72 patients had no psychotic illness. Bassett and colleagues noted predictors of schizophrenia in patients with 22q11.2 deletion syndrome were preterm birth (OR = 5.38; 95% CI, 1.63 – 17.75) and SGA birth weight (OR = 3.52; 95% CI, 1.34 – 9.22). Specifically, the positive predictive value of schizophrenia in the presence of preterm birth or SGA birth weight was 46%, and the negative predictive value in the absence of either variable was 83%. There was no significant difference in maternal age among patients with and without schizophrenia.

Disclosure: The researchers report no relevant financial disclosures.