Two Novel Missense Mutations in Nonketotic Hyperglycinemia

J Child Neurol. 2015 May;30(6):789-92. doi: 10.1177/0883073814535499. Epub 2014 May 16.


Nonketotic hyperglycinemia (OMIM no. 605899) is an autosomal recessively inherited glycine encephalopathy, caused by a deficiency in the mitochondrial glycine cleavage system. Here we report 2 neonates who were admitted to the hospital with complaints of respiratory failure and myoclonic seizures with an elevated cerebrospinal fluid/plasma glycine ratio and diagnosed as nonketotic hyperglycinemia. We report these cases as 2 novel homozygous mutations; a missense mutation c.593A>T (p.D198 V) in the glycine decarboxylase gene and a splicing mutation c.339G>A (Q113Q) in the aminomethyltransferase gene were detected. We would like to emphasize the genetic difference of our region in inherited metabolic diseases once again.

Keywords: mutation; nonketotic hyperglycinemia; novel.

Publication types

  • Case Reports

MeSH terms

  • Aminomethyltransferase / genetics*
  • Epilepsies, Myoclonic / genetics
  • Female
  • Genetic Predisposition to Disease
  • Glycine / blood
  • Glycine / cerebrospinal fluid
  • Glycine Dehydrogenase (Decarboxylating) / genetics*
  • Homozygote
  • Humans
  • Hyperglycinemia, Nonketotic / diagnosis*
  • Hyperglycinemia, Nonketotic / genetics*
  • Infant, Newborn
  • Male
  • Mutation, Missense
  • RNA Splicing
  • Respiratory Insufficiency / genetics


  • Glycine Dehydrogenase (Decarboxylating)
  • Aminomethyltransferase
  • Glycine