Early development and unstable genes in schizophrenia: preliminary results

Background. Trinucleotide repeats have been associated with schizophrenia, but the evidence, based on cross-sectional clinical information, is equivocal. Aims. To examine the relationship between genomic CAG/CTG repeat size and premorbid development in schizophrenia. Method. Early development and premorbid functioning of 22 patients with DSM-IV diagnosis of schizophrenia were assessed by parental interviews. Repeat expansion detection (RED) technique was used to measure genomic CAG/CTG repeat size, and PCR for CAG repeat size at the ERDA-1 and CTG 18.1 loci. Results. There was an inverse association between CAG/CTG size and perinatal complications. Patients with speech and motor developmental delay had larger repeats. The results were not due to expansion in the ERDA-1 and CTG 18.1 genes. Conclusions. CAG/CTG repeat expansion is associated with speech and motor developmental delay in schizophrenia. We propose that the developmental model may be useful for research into the genetics of schizophrenia.