Diagnosis of a case of 2q37 deletion syndrome by whole exome sequencing combined with whole genome low-coverage sequencing method

Objective: To analyze the clinical and genetic characteristics in a girl with 2q37 deletion syndrome.

Methods: Genomic DNA was extracted from peripheral blood samples taken from the patient and her parents, and was subjected to whole exome sequencing (WES) and low-coverage massively parallel copy number variation sequencing (CNV-seq). Candidate CNVs were verified by chromosomal karyotyping analysis and fluorescence quantitative PCR.

Results: The child was found to harbor a 6 Mb heterozygous deletion in 2q37 by WES and CNV-seq. The deletion has encompassed 98 genes with a range from GBX2 to LINC01881, and was de novo in origin. The result of fluorescence quantitative PCR was consistent with that of WES and CNV-seq. However, karyotyping analysis has failed to detect the deletion.

Conclusions: The patient was diagnosed with 2q37 deletion syndrome. Combined WES and CNV-seq method features high resolution, high throughput, and high sensitivity, which can significant raise the diagnostic rate for patients with mental disorder, multiple malformations and unknown syndromes.