Partial 9P Monosomy and Partial 8Q Trisomy by Adjacent 1 Segregation of Balanced Paternal Translocation Revealed by Molecular Karyotyping

ABSTRACT

We present here the details of a six-month male infant with multiple congenital anomalies and developmental delay with an apparently balanced karyotype - 46, XY, inv(9)(p11q13) - and revealed by oligo array CGH del(9)(p24.3p22.2) and dup(8) (q24.13q24.3). We used BlueGnome CytoChip oligo 2X105K microarray, v1.1, with 35kbp backbone resolution. Fluorescence in situ hybridization (FISH) with BAC clones was performed to confirm the array CGH results in the patient and his family. The proband's father and sister carried the same inversion in 9^th chromosome. It was initially assumed that the patient's imbalances are de novo, but the subsequent fine analysis of the FISH results and the karyotype reexamination revealed that it comes to familial reciprocal translocation between the 8^th chromosome and the inverted 9^th chromosome. The patient's phenotype was a result of adjacent 1 segregation during the 1^st meiotic division. The duplicated segment from 8^th chromosome harbors 84 OMIM genes and the deleted region in 9^th chromosome contains 40 OMIM genes. We discuss the role of the gene dosage change to find some genotype-phenotype correlations.

Keywords:

• developmental delay
• multiple congenital anomalies
• oligo array CGH
• reciprocal translocations