Table 2.
Metabolites in Physiological Fluids from Patients with SSADHD
| Metabolite | Urine (mmol/mol creatinine) | Plasma (μM) | Cerebrospinal fluid (μM) |
|---|---|---|---|
| GHB | 34-514 (n=10) (nl < 10) |
26-533 (n=17) (nl < 3) |
116-1110 (n=4) (nl < 3) |
| D-2-HG | 22-102 (n=7) (nl < 18) |
3.1-7.6 (n=4) (nl < 1) |
0.4-4.7 (n=6) (nl < 0.3) |
| SSA | 3-20 (n=13) (nl < 2) |
-- | 1280-2570 (n=3; nmol/L) (nl < 10) |
| DHHA | -- | -- | -- |
| GABA | ND | -- | 13.6-22.4 (n=4; total GABA) (nl < 12) |
| Homocarnosine | -- | -- | 14.8-41 (n=9) (nl < 10) |
| GBA | 4.6-35 (n=7) (nl < 5.8) |
-- | 0.04-0.32 (nl < 0.03) |
Legend: Abbreviations: GHB, γ-hydroxybutyric acid; D-2-HG, D-2-hydroxyglutaric acid; SSA, succinic semialdehyde; DHHA, 4,5-dihydroxyhexanoic acid; GABA, γ-aminobutyric acid; GBA, guanidinobutyrate; nl,normal; ND, not done. SSA in cerebrospinal fluid is reported in units of nmol/L. Total GABA refers to free and esterified forms of GABA (including esterified forms such as homocarnosine). See Fig. 2 for metabolic interconversions.