The clinical, cytogenetics and molecular characterization of inverted duplication/deletion of chromosome 8p in a boy with mental and motor retardation: Genotype-phenotype correlation in a case report

Background: Rearrangements that occur mainly through the non-allelic homologous recombination (NAHR) during maternal meiosis in short arms of chromosome 8 is relatively associated with various clinical spectrum. Aim: The objective of this study was to report cytogenetics and molecular characterization of a mental and motor retarded boy with short arm of chromosome 8 rearrangements [invdupdel(8p)] in this current case report. Subjects and methods: We report an 11-year-old boy with scoliosis, intellectual disability, mental-motor retardation and characteristic facial features. Agenesis of corpus callosum was detected with brain Magnetic Resonance Imaging (MRI) analysis. Derivative chromosome 8 structure was identified after conventional cytogenetics – karyotype analysis, Multiplex Ligation-Dependent Probe Amplification (MLPA) and Microarray-based Comparative Genomic Hybridization (aCGH) techniques. Genotype-phenotype correlation in the current proband case will be discussed. Results: Case was diagnosed as 46, XY, der (8), del (8) (p23.1) invdup (8) (p11.1-p23.1) by using advanced comparable techniques. Subtelomeric MLPA analysis showed deletion of FBXO25 gene which is located at 8p23.3 locus and FISH with subtelomeric probes for 8p shows also only deleted region. The microarray- CGH profilling showed 7,9 mb deletion for 8p23.1 and 31 mb duplication for 8p11.1 locuses. Conclusion: Results from the current case emphasized that the cases with clinical manifestations of such disorders extremely need to be examined by combined comparable genetics techniques such as; karyotyping, FISH, MLPA and chromosomal microarray for the accurate phenotype – genotype correlation. Keywords: Chromosomal rearrangement, Corpus callosum, Invdupdel(8p) Array-CGH, MLPA