Subtelomeric aberrations in Thai patients with idiopathic mental retardation and autism detected by multiplex ligation-dependent probe amplification
Article Category: Brief communication (Original)
Published Online: Jan 31, 2017
Page range: 501 - 509
DOI: https://doi.org/10.5372/1905-7415.0904.420
Keywords
© 2015 Sinitdhorn Rujirabanjerd, Oradawan Plong-on, Thanya Sripo, Pornprot Limprasert
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
Background
Chromosomal rearrangements involving telomeres account for approximately 1%-30% of causes of mental retardation (MR). It is therefore recommended that all cases of undiagnosed MR be screened for subtelomeric aberration. Nevertheless, resolution of a standard karyotyping using the G-banding technique is limited. Therefore, an additional technique with higher resolution should be performed to detect this type of anomaly.
Objectives
To screen for subtelomeric aberration in Thai patients with mental retardation and autism.
Methods
Multiplex ligation-dependent probe amplification (MLPA), was used to screen 114 Thai patients with idiopathic MR and 15 patients with autism. All positive results were confirmed by using a different set of MLPA probes or real-time PCR.
Results
We identified 5 patients with submicroscopic aberration in patients with MR. One patient had a submicroscopic deletion at the 1p36.33 region, which was confirmed by real-time PCR. There were 2 patients with subtelomeric duplication at the 15q11.2 and 11p15.5 regions sequentially. Two patients had the same duplication at the Xp22.33. region.
Conclusions
The present study shows that the incidence of a subtelomeric aberration in Thai patients with idiopathic MR is approximately the same reported previously (3.9%). Identifying these submicroscopic aberrations requires an advanced method with higher resolution than standard karyotyping. Although microarray techniques may be a more informative, they are costly and require an array facility, which are not widely available, especially in developing countries. Thus, MLPA in a routine cytogenetic test for MR patients with normal karyotypes in this setting can help to increase diagnostic yield.