title: Genotype-phenotype correlation of SMN locus genes in spinal muscular atrophy children from Argentina.
abstract: OBJECTIVE
  Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder, considered one of the leading causes of infant mortality. It is caused by mutations in the SMN1 gene. A highly homologous copy of this gene named SMN2 and other neighbouring genes, SERF1A and NAIP, are considered phenotypic modifiers of the disease. In recent years, notable advances have been made in SMA research regarding evaluation, prognosis, and therapeutic options. Thus, genotype-phenotype studies in SMA are important to stratify patients for motor function tests and for envisaged clinical trials. The aim of this study was to provide clinical and molecular data of a series of Argentinean children with SMA to establish a comprehensive genotype-phenotype correlation.
  
  
  METHODS
  144 Argentinean children with SMA (56 children with type I, 58 with type II, and 30 with type III) were evaluated. The copy number of SMN2, SERF1A, and NAIP genes was established using MLPA (Multiplex Ligation-dependent Probe Amplification) and then correlated with the patients clinical subtypes. To improve clinical characterization we considered the initial symptoms that prompted the consultation, age of acquisition of motor abilities to independent walking and age at loss of gait. We also evaluated clinical and molecular features of sibling pairs in seven families.
  
  
  RESULTS
  A strong correlation was observed between the SMN2 copy number and SMA phenotype while SERF1A and NAIP copy number showed a moderate correlation. We observed intra- and inter-family differences among the SMA types.
  
  
  CONCLUSIONS
  This first genotype-phenotype correlation study in Argentinean SMA children provides data to improve patient stratification and define more adequate follow-up parameters.
authors: Laboratorio de Biología Molecular, Servicio de Genética, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Sofía
authors: S
authors: Medrano
authors: Servicio de Neurología, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Soledad
authors: S
authors: Monges
authors: Laboratorio de Biología Molecular, Servicio de Genética, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Luis Pablo
authors: LP
authors: Gravina
authors: Servicio de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; CIBERER U-705, Barcelona, Spain.
authors: Laura
authors: L
authors: Alías
authors: Servicio de Kinesiología, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Julieta
authors: J
authors: Mozzoni
authors: Laboratorio de Biología Molecular, Servicio de Genética, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Hilda Verónica
authors: HV
authors: Aráoz
authors: Servicio de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain; CIBERER U-705, Barcelona, Spain.
authors: Sara
authors: S
authors: Bernal
authors: Servicio de Genética, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Angélica
authors: A
authors: Moresco
authors: Laboratorio de Biología Molecular, Servicio de Genética, Hospital de Pediatría Garrahan, Buenos Aires, Argentina.
authors: Lilien
authors: L
authors: Chertkoff
authors: Department of Clinical and Molecular Genetics, Hospital Valle Hebron, Barcelona, Spain; CIBERER U-705, Barcelona, Spain. Electronic address: etizzano@vhebron.net.
authors: Eduardo
authors: E
authors: Tizzano
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D001118:Argentina; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D018628:Gene Dosage; D005838:Genotype; D006801:Humans; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics; D051616:Neuronal Apoptosis-Inhibitory Protein / Q000235:genetics; D010641:Phenotype; D012189:Retrospective Studies; D014897:Spinal Muscular Atrophies of Childhood / Q000453:epidemiology / Q000235:genetics*; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics*; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics; D055815:Young Adult
chemical_list: C496800:NAIP protein, human; D009419:Nerve Tissue Proteins; D051616:Neuronal Apoptosis-Inhibitory Protein; C114841:SERF1A protein, human; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein
keywords: Multiplex Ligation-dependent Probe Amplification (MLPA); Neuronal apoptosis inhibitory protein gene (NAIP); Small EDRK-rich factor 1A (SERF1A); Spinal muscular atrophy (SMA); Survival motor neuron 1 gene (SMN1); Survival motor neuron 2 gene (SMN2)