<abstract xmlns="http://www.w3.org/1999/xhtml"><sec id="j_1905-7415.0904.420_s_001_w2aab3b7b7b1b6b1aab1c16b1Aa"><h3>Background</h3><p>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.</p></sec><sec id="j_1905-7415.0904.420_s_002_w2aab3b7b7b1b6b1aab1c16b2Aa"><h3>Objectives</h3><p>To screen for subtelomeric aberration in Thai patients with mental retardation and autism.</p></sec><sec id="j_1905-7415.0904.420_s_003_w2aab3b7b7b1b6b1aab1c16b3Aa"><h3>Methods</h3><p>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.</p></sec><sec id="j_1905-7415.0904.420_s_004_w2aab3b7b7b1b6b1aab1c16b4Aa"><h3>Results</h3><p>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.</p></sec><sec id="j_1905-7415.0904.420_s_005_w2aab3b7b7b1b6b1aab1c16b5Aa"><h3>Conclusions</h3><p>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.</p></sec></abstract>

BackgroundChromosomal 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.ObjectivesTo screen for subtelomeric aberration in Thai patients with mental retardation and autism.MethodsMultiplex 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.ResultsWe 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.ConclusionsThe 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.

Subtelomeric aberrations in Thai patients with idiopathic mental retardation and autism detected by multiplex ligation-dependent probe amplification

Department of Pathology, Faculty of Medicine

Asian Biomedicine

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

BackgroundChromosomal rearrangements involving telomeres account for approximately 1%-30% of causes of mental retardation (MR). It is therefore recommended...

Patient	No. Duplication	Verification Method	Sex	Age	Origin	Neurological symptoms	Other anomaly
1	15q11.2	MLPA	Male	7	de novo	MR	-
2	Xp22.3	MLPA	Male	6	N/A	MR	N/A
3	Xp22.3	MLPA	Male	6	N/A	MRseizure	- Bilateral cleft lips
							- Left cleft palate
							- Thalassemia hemoglobin E trait
4	11p15.5	MLPA	Female	3	N/A	MR	- Choanal atresia
							- Coloboma of right upper and lower eyelids
							- Right cleft lip
	Deletion
5	1p36.33	Real-time PCR	Female	1	N/A	MR	Flat head with frontal bossing

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
Autism, mental retardation, MLPA, subtelomere

© 2015 Sinitdhorn Rujirabanjerd, Oradawan Plong-on, Thanya Sripo, Pornprot Limprasert

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Figure 1

Figure 2

Summary of MLPA results and clinical symptoms of all positive cases

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

KeywordsAutism, mental retardation, MLPA, subtelomere

© 2015 Sinitdhorn Rujirabanjerd, Oradawan Plong-on, Thanya Sripo, Pornprot Limprasert

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Figure 1

Figure 2

Summary of MLPA results and clinical symptoms of all positive cases

Keywords
Autism, mental retardation, MLPA, subtelomere