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IllnessHyperglycinemia, non-ketotic; differential diagnosis

Summary

Short information

Comprehensive differential diagnostic panel for Hyperglycinemia, non-ketotic; differentrial diagnosis, comprising 8 guideline-curated genes [3 core genes and 3 core candidate genes) and altogether 19 curated genes, respectively, according to the clinical signs

ID
HP4400
Number of genes
18 Accredited laboratory test
Examined sequence length
7,8 kb (Core-/Core-canditate-Genes)
28,3 kb (Extended panel: incl. additional genes)
Analysis Duration
on request
Material
  • EDTA-anticoagulated blood (3-5 ml)
Diagnostic indications

NGS +

[[Sanger]]

 

Gene panel

Selected genes

NameExon Length (bp)OMIM-GHeredity
AMT1212AR
BOLA3324AR
GCSH522AR
GLDC3063AR
GLRX5474AR
SLC6A92121AR
ALDH7A11620AR
HCFC16108XLR
IBA571071AR
IVD1182AR
LIAS990AR
LIPT2982AR
MMUT2253AR
NFU1765AR
PCCA2187AR
PCCB1620AR
PLPBP995AR
PNPO786AR

Informations about the disease

Clinical Comment

Non-ketotic hyperglycemia (NKH) is a rare metabolic disorder caused by defects in the breakdown of gylcine leading to its accumulation. The classic form ranges from severe to mild symptoms, with the former typically occurring in the first few days of life with reduced muscle tone, lethargy, seizures, coma and apnea. As the disease progresses, developmental delay becomes evident and seizures worsen. Attenuated classic NKH may occur in the neonatal period or later in infancy and developmental delays are highly variable. Hyperactivity and behavioral problems sometimes occur. The clinical picture of NKH variants varies depending on the mutated gene and the specific mutation. The differential diagnosis of NKH is very complex and includes cofactor deficiency and impaired regulation/inhibition of the "glycine cleavage enzyme system" as well as glycine transport defects (see additional genes). The DNA diagnostic yield is about 95%, provided that the function of the glycine cleavage enzyme system is proven. Inconspicuous genetic findings do not imply a definite exclusion of the clinical suspected diagnoses.

References: https://www.ncbi.nlm.nih.gov/books/NBK1357/

https://www.ncbi.nlm.nih.gov/books/NBK92946/

https://www.ncbi.nlm.nih.gov/books/NBK465013/

 

Synonyms
  • Alias: Glyzin-Enzephalopathie; Hyperglycinämie, nicht-ketotische; Glycin-Enzephalopathie
  • Allelic: Anemia, sideroblastic, 3, pyridoxine-refractory (GLRX5)
  • DD: Epilepsy, pyridoxine-dependent (ALDH7A1)
  • DD: Isovaleric acidemia (IVD)
  • DD: Mental retardation, XL 3 [methylmalonic acidemia + homocysteinemia, cblX type]
  • DD: Methylmalonic aciduria, mut(0) type (MMUT)
  • DD: Multiple mitochondrial dysfunctions syndrome 1 (NFU1)
  • DD: Multiple mitochondrial dysfunctions syndrome 3 (IBA57)
  • DD: Propionicacidemia (PCCA, PCCB)
  • DD: Pyridoxamine 5'-phosphate oxidase deficiency (PNPO)
  • Encephalopathy, neonatal severe, with lactic acidosis and brain abnormalities (LIPT2)
  • Epilepsy, early-onset, vitamin B6-dependent (PLPBP)
  • Glycine encephalopathy (AMT, GLDC)
  • Glycine encephalopathy with normal serum glycine (SLC6A9)
  • Glycine encephalopathy? (GCSH)
  • Hyperglycinemia, lactic acidosis + seizures (LIAS)
  • Hyperglycinuria (SLC36A2)
  • Hyperglycinuria, benign (SLC6A18)
  • Iminoglycinuria, digenic (SLC36A2, SLC6A19/SLC6A20)
  • Multiple mitochondrial dysfunctions syndrome 2 with hyperglycinemia (BOLA3)
  • Spasticity, childhood-onset, with hyperglycinemia (GLRX5)
Heredity, heredity patterns etc.
  • AR
  • XLR
OMIM-Ps
  • Multiple OMIM-Ps
ICD10 Code
E72.-

Bioinformatics and clinical interpretation

No text defined