Atypical copy number abnormalities in 22q11.2 region: Report of three cases

作者：Molck Miriam Coelho; Vieira Tarsis Paiva; Sgardioli Ilaria Cristina; Simioni Milena; dos Santos Ana Paula; Souza Josiane; Monteiro Fabiola Paoli; Gil da Silva Lopes Vera Lucia^*

来源：European Journal of Medical Genetics, 2013, 56(9): 515-520.

DOI：10.1016/j.ejmg.2013.07.002

• 22q11.2 deletion
• Atypical copy number abnormalities
• Distal 22q11.2 deletion
• Multiplex-ligation dependent probe amplification
• Array genomic Hybridization
• Genotype-phenotype correlation

The 22q11.2 Deletion Syndrome (22q11.2DS) is the most common microdeletion syndrome in humans, with a highly variable phenotype. This chromosomal region contains low copy repeat (LCR) sequences that mediate non-allelic homologous recombination which predispose to copy number abnormalities at this locus. This article describes three patients investigated for suspicion of 22q11.2DS presenting atypical copy number abnormalities overlapping or not with the common similar to 3 Mb deletion. They were investigated by G-banding karyotype, Multiplex-ligation dependent probe amplification (MLPA) and array Genomic Hibridization (aGH). Clinical and molecular data were compared with literature, in order to contribute to genotype-phenotype correlation. Atypical chromosomal abnormalities were detected: 3.6 Mb deletion at 22q11.21-q11.23 between LCRs B-F in patient 1 and approximately 1.5 Mb deletion at 22q11.21-q11.22 between LCRs D-E in patients 2 and 3. The breakpoints detected in patient 1 have not been previously described. These findings exemplify the complexity and genetic heterogeneity observed in 22q11.2 region and corroborates the idea that genetic modifiers contribute to the phenotypic variability observed in proximal and distal 22q11.2 deletion syndromes.

• 出版日期2013-9