title: Reviewing Large LAMA2 Deletions and Duplications in Congenital Muscular Dystrophy Patients.
abstract: BACKGROUND
  Congenital muscular dystrophy (CMD) type 1A (MDC1A) is caused by recessive mutations in laminin-α2 (LAMA2) gene. Laminin-211, a heterotrimeric glycoprotein that contains the α2 chain, is crucial for muscle stability establishing a bond between the sarcolemma and the extracellular matrix. More than 215 mutations are listed in the locus specific database (LSDB) for LAMA2 gene (May 2014).
  
  
  OBJECTIVE
  A limited number of large deletions/duplications have been reported in LAMA2. Our main objective was the identification of additional large rearrangements in LAMA2 found in CMD patients and a systematic review of cases in the literature and LSDB.
  
  
  METHODS
  In four of the fifty-two patients studied over the last 10 years, only one heterozygous mutation was identified, after sequencing and screening for a frequent LAMA2 deletion. Initial screening of large mutations was performed by multiplex ligation-dependent probe application (MLPA). Further characterization implied several techniques: long-range PCR, cDNA and Southern-blot analysis.
  
  
  RESULTS
  Three novel large deletions in LAMA2 and the first pathogenic large duplication were successfully identified, allowing a definitive molecular diagnosis, carrier screening and prenatal diagnosis. A total of fifteen deletions and two duplications previously reported were also reviewed. Two possible mutational "hotspots" for deletions may exist, the first encompassing exons 3 and 4 and second in the 3' region (exons 56 to 65) of LAMA2.
  
  
  CONCLUSIONS
  Our findings show that this type of mutation is fairly frequent (18.4% of mutated alleles) and is underestimated in the literature. It is important to include the screening of large deletions/duplications as part of the genetic diagnosis strategy.
authors.affiliation: Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto de Magalhães, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Oliveira
authors.affiliation: Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto de Magalhães, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Gonçalves
authors.affiliation: Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto de Magalhães, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Márcia E
authors.initials: ME
authors.lastname: Oliveira
authors.affiliation: Unidade de Neuropediatria, Centro de Desenvolvimento da Criança Luís Borges, Hospital Pediátrico de Coimbra, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Fineza
authors.affiliation: Centro de Estudos do Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Rita C M
authors.initials: RC
authors.lastname: Pavanello
authors.affiliation: Centro de Estudos do Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Mariz
authors.initials: M
authors.lastname: Vainzof
authors.affiliation: Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: Elsa
authors.initials: E
authors.lastname: Bronze-da-Rocha
authors.affiliation: Unidade de Genética Molecular, Centro de Genética Médica Dr. Jacinto de Magalhães, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Rosário
authors.initials: R
authors.lastname: Santos
authors.affiliation: Departamento de Microscopia, Laboratório de Biologia Celular, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.
authors.forename: Mário
authors.initials: M
authors.lastname: Sousa