Newly defined Unbalanced distributions of paternal balanced chromosomal translocation and review of the literature

Balanced chromosomal re-arrangements (BCR) are re-arrangements with no loss or gain of genetic material and usually not associated with clinical abnormalities. However, BCR carriers may have children with a chromosomal anomaly as a result of an unbalanced transfer of chromosomes to the offsprings. The children with unbalanced chromosomal translocations may exhibit many congenital anomalies, especially motor-mental retardasyon. We report unbalanced translocation and multiple congenital anomalies in two siblings. Chromosomal microarray analysis was performed on the both siblings using Agilent Oligonucleotide Microarray 8 × 60K. Chromosomal microarray analysis showed partial deletion in 5p and partial duplication in 7q (arr[GRCh37] 5p15.33-p15.2x1, 7q36.1-q36.3x3) in one sibling, and partial duplication in 5p and partial deletion in 7q (arr[GRCh37] 5p15.33-p15.2x3, 7q36.1-q36.3x1) in the other sibling were detected. Subtelomeric Fluorescent In Situ Hybridization (FISH) analysis was performed on the entire family using Cytocell Telomark Probe. The father was found to have 46,XY.ish t(5;7)(p15-,q36+;q36-,p15+) balanced chromosomal translocation structure, while the mother was found to have 46,XX normal chromosome structure. To the best of our knowledge, 5p partial trisomy+7q partial monosomy and 5p partial monosomy+7q partial trisomy have not been previously reported. These findings provide us with the conclusion that copy number variation analysis is important in the diagnosis of congenital anomalies, especially motor-mental retardation