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Subtelomeric rearrangements and copy number variations in people with intellectual disabilities


  • Conflict of Interest: The authors declare no conflict of interest.

Maria Isabel Melaragno, Universidade Federal de São Paulo, Rua Botucatu 740, Vila Clemetino, São Paulo, SP 04023-900, Brazil (e-mail:


Background  The most prevalent type of structural variation in the human genome is represented by copy number variations that can affect transcription levels, sequence, structure and function of genes.

Method  In the present study, we used the multiplex ligation-dependent probe amplification (MLPA) technique and quantitative PCR for the detection of copy number variation in 132 intellectually disabled male patients with normal karyotypes and negative fragile-X-testing.

Results  Ten of these patients (7.6%) showed copy number variation in the subtelomeric regions, including deletions and duplications.

Discussion  Duplications of the SECTM1 gene, located at 17q25.3, and of the FLJ22115 gene, located at 20p13, could be associated with phenotype alterations. This study highlights the relevance in the aetiology of intellectual disability of subtelomeric rearrangements that can be screened by MLPA and other molecular techniques.