title: [Spinal muscular atrophy: frequent cause of congenital hypotonia in Morocco].
abstract: BACKGROUND
  Congenital hypotonia is a non specific symptom frequently seen in newborns and infants, and whose etiological diagnosis is often difficult due to the lack of specialized and affordable explorations. Childhood-onset proximal spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by degeneration of the anterior horn cells of the spinal cord, leading to progressive paralysis with muscular atrophy. In more than 95% of the cases, it results from deletion of exon 7 of the SMN gene localized on 5q13, easily identified by molecular biology.
  
  
  OBJECTIVE
  To determine the prevalence of the deletion of exon 7 of the SMN gene in congenital hypotonia with an unknown cause in Morocco.
  
  
  METHODS
  We investigated the deletion of exon 7 of the SMN gene in 87 newborns and infants with congenital hypotonia. The cause of congenital hypotonia could not be determined in 60 of them, while 27 had electrophysiological evidence for an involvement of the anterior horn cells.
  
  
  RESULTS
  The homozygous deletion of the SMN gene was detected in 23 of the newborns with unknown cause for hypotonia (38%) and in 21 of the infants whose electromyogram suggested infantile spinal amyotrophy (78%).
  
  
  CONCLUSIONS
  This study underlines the advantages of a systematic search for the deletion of exon 7 of the SMN gene in every infant suffering from congenital hypotonia due to an unknown cause, particularly when the child's vital prognosis is at stake. This genetic test, easily implemented, should be systematically proposed after an attentive clinical evaluation in countries where the etiological diagnosis of congenital hypotonia is not systematic.
authors: Département de génétique médicale, institut national d'hygiène, Rabat, Maroc.
authors: A
authors: A
authors: Sbiti
authors: I
authors: I
authors: Ratbi
authors: Y
authors: Y
authors: Kriouile
authors: A
authors: A
authors: Sefiani
mesh_terms: D002675:Child, Preschool; D004247:DNA; D004576:Electromyography; D005091:Exons; D017353:Gene Deletion; D005817:Genetic Counseling; D005820:Genetic Testing; D015894:Genome, Human; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009018:Morocco / Q000453:epidemiology; D009123:Muscle Hypotonia / Q000151:congenital* / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D015995:Prevalence; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics; D055540:Survival of Motor Neuron 2 Protein / Q000235:genetics
chemical_list: C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; D004247:DNA