Prenatal detection of a 3q29 microdeletion in a fetus with ventricular septum defect: A case report and literature review

RATIONALE: Chromosomal 3q deletion is a recurrent genomic alternation, which is rarely reported in clinic. PATIENT CONCERNS: A 27-year-old woman underwent amniocentesis for cytogenetic analysis and single nucleotide polymorphism (SNP) array analysis at 27 weeks of gestation, due to ventricular septum defect in prenatal ultrasound findings. DIAGNOSES: G-banding analysis showed the karyotype of the fetus was normal and the couple also had normal karyotypes. However, SNP array detected a 1.71 Mb microdelection in 3q29, which was described as arr[hg19]3q29(194184392–195887205) × 1. There are 12 genes located in this locus. INTERVENTIONS: The couple refused SNP array to testify the 3q29 microdeletion was inherited or de novo and they chose termination of pregnancy. OUTCOMES: The deleted region in the fetus overlapped with part 3q29 microdeletion syndrome, which was characterized by learning disability, speech delay, mental deficiency, ocular abnormalities and craniofacial features. In addition, no similar/overlapping 3q29 microdeletion cases were reported according to the published literature and database. LESSONS: For the chromosomal microscopic imbalances partially overlapping with the defined pathogenic syndrome, deleted/duplicated size, genetic materials and phenotypic diversity should be taken into consideration when genetic counseling is offered by the clinicians.