Prenatal findings and delineation of de novo concurrent partial trisomy 7q(7q31.2 → qter) and partial monosomy 6q(6q26 → qter) by high-resolution array CGH

Abstract

Objective. We investigated the application of microarray-based comparative genomic hybridization (array CGH) on a fetus showing hemivertebrae and intra-abdominal mass at 15 weeks.

Methods. Conventional karyotyping and high-resolution array CGH techniques using 244K CGH microarray were performed to investigate the possibility of genomic imbalance on the opted chorionic villus sample.

Results. G-banded fetal chromosome analysis showed 46,XY,der(6)t(6;7)(q26;q31.2)pat. Whole genome scan by array CGH fine mapped the origin of the aberrant chromosomes to be a partial single copy gain of 42.5 Mb from chromosome region 7:116266547 → qter and concurrent partial single copy loss of 8.1 Mb from chromosome region 6:162756975 → qter. Pathological examination of the abortus showed gastrointestinal malformations, hemivertebrae with scoliosis, clinodactyly and club feet.

Conclusions. Prenatal and perinatal findings of concurrent trisomy 7q and monosomy 6q were unique. This study demonstrated array CGH can interrogate the entire genome at a resolution and rapidity unattainable by conventional cytogenetic techniques and may have wide application in prenatal diagnosis.

Keywords:

• Prenatal diagnosis
• array CGH
• partial trisomy 7q
• partial monosomy 6q
• karyotyping
• perinatal findings

Acknowledgements

This work was supported by the Direct grant for research, from the Chinese University of Hong Kong, The Hong Kong O&G Trust Fund, the University Research Grant from Agilent Technologies and Seed funding form Li Ka Shing Institute of Health Sciences, Hong Kong. We thank Liu YM and Wong HK for the technical assistance. RGC earmarked grant, Hong Kong (Project ID: 469307), The Hong Kong O&G Trust Fund and Agilent university research grant from Agilent Technologies. (Project ID: 6902238).