Table 1.

CSF and Plasma Glycine Concentration (µmol/L) in Nonketotic Hyperglycinemia (NKH)

NKH PhenotypeNormal Control
Severe NKH 1Attenuated NKH 1
CSF glycine concentration 228 (40-510) 299 (41-230)<20 µmol/L 3
Plasma glycine concentration 1133 (342-2363)822 (342-1590)125-450 3, 4
CSF:plasma glycine ratio 5 0.22 (0.09-0.45)0.13 (0.04-0.22)≤0.02
1.

Average (range) [Swanson et al 2015]

2.

The author knows of very rare cases of intermittently normal CSF glycine.

3.

Normal values vary with age. Both CSF and plasma glycine concentrations are higher in the neonatal period and decrease rapidly in the first months of life (e.g., at age >1 year, normal values for CSF glycine concentration are <12 µmol/L and for plasma glycine concentration are <350 µmol/L).

4.
5.

Samples must be obtained simultaneously.

From: Nonketotic Hyperglycinemia

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