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GENATLAS PHENOTYPE
last update : 24-04-2013
Symbol NKH1
Location 9p24-p23
Name hyperglycinemia 1, non ketotic
Corresponding gene GLDC
Other symbol(s) NKH
Main clinical features
  • presenting in most patients in the neonatal period with lethargy, hypotonia, myoclonic jerks, apnea, leading to early death
  • acute encephalopathy in the neonatal period, although later, atypical presentations have also been reported
  • adult form, with mild hyperglycinemia, infantile hypotonia, mental retardation, behavioral hyperirritability, and aggressive outbursts, learning disability and intermittent choreoathetosis during febrile illnesses
    • Genetic determination autosomal recessive
    Function/system disorder metabolism/aminoacids
    Type disease
    Gene product
    Name glycine-cleavage system, P protein (GLDC)
    Mechanism(s)
    Gene mutationChromosome rearrangementEffectComments
    deletion   abnormal protein/loss of function  
    Remark(s) . seven of the 32 GLDC missense mutations were clustered in exon 19, which encodes the cofactor-binding site Lys754 (PMID:16550403 )
    Genotype/Phenotype correlations missense mutations (A389V and R739H) found in mild adult form