title: Multiplex ligation-dependent probe amplification workflow for the detection of submicroscopic chromosomal abnormalities in patients with developmental delay/intellectual disability.
abstract: BACKGROUND
  Array based comparative genomic hybridization (arrayCGH) has been increasingly used as the method of choice for diagnosis of patients with unexplained developmental delay/intellectual disability (DD/ID) but is not universally available for the high throughput use in routine practice. The next-generation sequencing (NGS) techniques, emerging as a new tool in clinical diagnostics, are at present quite labour-intensive and expensive. Since multiplex ligation-dependent probe amplification (MLPA) is relatively fast, easily interpreted and cost-effective, it is still a method of choice for screening large cohorts of patients with DD/ID.
  
  
  RESULTS
  We prospectively studied a cohort of 150 patients with DD/ID with or without dysmorphic features or additional congenital abnormalities. We used two distinct MLPA kits, SALSA P036 and P070, for subtelomere screening and MLPA kit SALSA P245 for the 21 common microdeletion syndromes. Subtelomere analysis was performed by both kits in all patients. All imbalances were verified by follow-up MLPA kits. The MLPA analysis revealed chromosome aberrations in 21 (14%) cases: 11 subtelomeric rearrangements and 10 microdeletions.
  
  
  CONCLUSIONS
  We have presented the results of the investigation of patients with DD/ID obtained by using a combination of the MLPA sets for subtelomere aberrations and microdeletion syndromes followed by the confirmation of the aberrant results by the region-specific MLPA kits. The use of two subtelomeric kits per patient and investigation of all aberrations by follow-up sets has reduced the rate of false positive and negative results and improved the diagnostic yield. The relatively low cost, simplicity and reliability makes MLPA an effective first-tier cytogenetic diagnostic test for screening large cohorts of DD/ID patients.
authors: Department of Pediatrics, Division of Medical Genetics, Children's Hospital Zagreb, Medical School University of Zagreb, Klaiceva 16, 10000, Zagreb, Croatia. leona.more@yahoo.com.
authors: Leona Morozin
authors: LM
authors: Pohovski
authors: Katja K
authors: KK
authors: Dumic
authors: Ljubica
authors: L
authors: Odak
authors: Ingeborg
authors: I
authors: Barisic
references: Eur J Med Genet. 2007 Jan-Feb;50(1):33-42
references: 17090394
references: Clin Genet. 2006 Jan;69(1):58-64
references: 16451137
references: Hum Mutat. 2005 Nov;26(5):477-86
references: 16170807
references: Am J Hum Genet. 2010 May 14;86(5):749-64
references: 20466091
references: Am J Med Genet A. 2011 Feb;155A(2):343-8
references: 21271651
references: Clin Genet. 2012 Jun;81(6):503-10
references: 22375550
references: Eur J Hum Genet. 1997 Jan-Feb;5(1):1-8
references: 9156314
references: Semin Pediatr Neurol. 2001 Sep;8(3):135-46
references: 11575843
references: Am J Med Genet A. 2005 Dec 15;139(3):231-3
references: 16278905
references: Eur J Hum Genet. 2009 Nov;17(11):1394-402
references: 19436329
references: Am J Med Genet C Semin Med Genet. 2007 Nov 15;145C(4):335-45
references: 17910076
references: Indian J Pediatr. 2009 Oct;76(10):1027-31
references: 19907935
references: Eur J Med Genet. 2008 Mar-Apr;51(2):93-105
references: 18032123
references: Hum Mutat. 2004 Jan;23(1):17-21
references: 14695528
references: Eur J Med Genet. 2011 Jul-Aug;54(4):e425-32
references: 21457803
references: J Med Genet. 2004 Dec;41(12):892-9
references: 15591274
references: Expert Rev Mol Diagn. 2011 Jun;11(5):521-32
references: 21707460
references: Expert Rev Mol Diagn. 2011 Apr;11(3):333-43
references: 21463242
references: Pediatrics. 2006 Jun;117(6):2304-16
references: 16740881
references: Mol Cytogenet. 2010 Apr 15;3:9
references: 20398301