De Novo Pericentric Inversion of Chromosome 9 in Congenital Anomaly

PURPOSE The pericentric inversion of chromosome 9 is one of the most common structural balanced chromosomal variations and has been found in both normal populations and patients with various abnormal phenotypes and diseases. The aim of this study was to re-evaluate the clinical impact of inv(9)(p11q13). MATERIALS AND METHODS We studied the karyotypes of 431 neonates with congenital anomalies at the Pediatric Clinic in Ajou University Hospital between 2004 and 2008 and retrospectively reviewed their clinical data. RESULTS Chromosomal aberrations were detected in 60 patients (13.9%). The most common type of structural abnormality was inv(9)(p11q13), found in eight patients. Clinical investigation revealed that all eight cases with inv(9)(p11q13) had various congenital anomalies including: polydactyly, club foot, microtia, deafness, asymmetric face, giant Meckel's diverticulum, duodenal diaphragm, small bowel malrotation, pulmonary stenosis, cardiomyopathy, arrhythmia, and intrauterine growth restriction. The cytogenetic analysis of parents showed that all of the cases were de novo heterozygous inv(9)(p11q13). CONCLUSION Since our results indicate that the incidence of inv(9)(p11q13) in patients with congenital anomalies was not significantly different from the normal population, inv(9)(p11q13) does not appear to be pathogenic with regard to the congenital anomalies. Some other, to date unknown, causes of the anomalies remain to be identified.