The importance of systematic genetic approach to familial schizophrenia cases and discussion of cryptic mosaic X chromosome aneuploidies in schizophrenia pathogenesis

Abstract

Objective. The aim of this study is to contribute to the understanding of schizophrenia genetics by using efficient algorithmic examination techniques including dysmorphic examination, karyotyping, and Fluoresence in situ hybridization (FISH). Methods. In this study we have investigated 20 familial schizophrenia patients from Turkey who had an affected first-degree relative. Dysmorphic examination of the schizophrenia cases and their relatives have been performed. High resolution banding (HRB), specific centromeric, subtelomeric and 22q11.2 region FISH probes were used for genotyping of patients. Results. Dysmorphic examination revealed ear, palate, nose, columella anomalies, and obesity in contributing patients, and the pale skin was noticed. The medical histories and clinical findings of two schizophrenia twins were almost identical. HRB study demonstrated the presence of 46,XX[55]/47,XXX[4]/48,XXXX[1] constitution in a paranoid schizophrenia case and 46,XX[67]/45,X[5] karyotype in her mother. FISH studies aiming subtelomeric chromosomal regions revealed no rearrangements and 22q11.2 regions were intact in all of the patients. Conclusions. The parental gonadal mosaicism lying at the origin of the mitotic aneuploidy may be the reason for mosaic X chromosome aneuploidies in our mother–daughter schizophrenia couple. Mosaic X chromosome aneuploidies may accompany schizophrenia cases and may contribute to pathogenesis of familial schizophrenia.

Key Words::

• Aneuploidy
• FISH
• schizophrenia
• subtelomeric rearrangement
• pale skin
• X chromosome

Acknowledgement

The study was supported by grants TF.01/2007-06, Scientific Research Projects Unit of Gazi University. The authors like to thank Halise Devrimci, Associate Professor of Psychiatry, Ankara University Faculty of Medicine, for referring one parent to our study.

Statement of interest

None of the authors have any conflict of interest.