Case report
Chromosome 12q24.31-q24.33 deletion causes multiple dysmorphic features and developmental delay: First mosaic patient and overview of the phenotype related to 12q24qter defects
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* Corresponding author: Namik Kaya nkaya@kfshrc.edu.sa
1 Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
2 Department of Zoology, School of Basic Sciences, King Saud University, Riyadh, 11211, Saudi Arabia
3 Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
4 Department of Pediatrics, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
5 Yildiz Technical University, Besiktas, 34349, Istanbul, Turkey
Molecular Cytogenetics 2011, 4:9 doi:10.1186/1755-8166-4-9
Published: 2 April 2011Abstract
Background
Genomic imbalances of the 12q telomere are rare; only a few patients having 12q24.31-q24.33 deletions were reported. Interestingly none of these were mosaic. Although some attempts have been made to establish phenotype/genotype interaction for the deletions in this region, no clear relationship has been established to date.
Results
We have clinically screened more than 100 patients with dysmorphic features, mental retardation and normal karyotype using high density oligo array-CGH (aCGH) and identified a ~9.2 Mb hemizygous interstitial deletion at the 12q telomere (Chromosome 12: 46,XY,del(12)(q24.31q24.33) in a severely developmentally retarded patient having dysmorphic features such as low set ears, microcephaly, undescended testicles, bent elbow, kyphoscoliosis, and micropenis. Parents were found to be not carriers. MLPA experiments confirmed the aCGH result. Interphase FISH revealed mosaicism in cultured peripheral blood lymphocytes.
Conclusions
Since conventional G-Banding technique missed the abnormality; this work re-confirms that any child with unexplained developmental delay and systemic involvement should be studied by aCGH techniques. The FISH technique, however, would still be useful to further delineate the research work and identify such rare mosaicism. Among the 52 deleted genes, P2RX2, ULK1, FZD10, RAN, NCOR2 STX2, TESC, FBXW8, and TBX3 are noteworthy since they may have a role in observed phenotype.