title: Asparagine Synthetase Deficiency: New Inborn Errors of Metabolism.
abstract: BACKGROUND
  Asparagine synthetase deficiency (ASD) is a newly identified neurometabolic disorder characterized by severe congenital microcephaly, severe global developmental delay, intractable seizure disorder, and spastic quadriplegia. Brain MRI showed brain atrophy, delayed myelination, and simplified gyriform pattern.
  
  
  METHODS
  We report ASD deficiency in a 2- and 4-year-old sibling. On them, we described clinical, biochemical, and molecular findings, and we compared our results with previously reported cases.
  
  
  RESULTS
  We identified a homozygous novel missense mutation in ASNS gene in both probands and we demonstrated low CSF and plasma asparagine in both patients.
  
  
  CONCLUSIONS
  Clinicians should suspect ASD deficiency in any newborn presented with severe congenital microcephaly followed by severe epileptic encephalopathy and global developmental delay. CSF asparagine level is low in this disorder while plasma may be low.
authors: Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia, dralfadhelm@gmail.com.
authors: Majid
authors: M
authors: Alfadhel
authors: Muhammad Talal
authors: MT
authors: Alrifai
authors: Daniel
authors: D
authors: Trujillano
authors: Hesham
authors: H
authors: Alshaalan
authors: Ali
authors: A
authors: Al Othaim
authors: Shatha
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authors: Al Rasheed
authors: Hussam
authors: H
authors: Assiri
authors: Abdulrhman A
authors: AA
authors: Alqahtani
authors: Manal
authors: M
authors: Alaamery
authors: Arndt
authors: A
authors: Rolfs
authors: Wafaa
authors: W
authors: Eyaid