Diagnosis | Sample | Investigation |
---|---|---|
Pyridoxine-dependent seizures* | Urine, CSF or plasma | α-Amino adipic semialdehyde |
Pipecolic acid | ||
Pyridoxal phosphate-dependent seizures* | CSF | Pyridoxal phosphate |
3-Phosphoglycerate dehydrogenase deficiency* | CSF | Serine |
GLUT-1deficiency* | CSF and plasma simultaneous | Glucose (low CSF/plasma ratio <0.46) |
Sample plasma first to avoid stress-related elevation and false-positive result | ||
Biotinidase deficiency* | Plasma | Biotinidase |
Non-ketotic hyperglycinaemia | CSF and plasma | Amino acids (raised CSF/plasma glycine ratio >0.09) |
Molybdenum cofactor deficiency and sulphite oxidase deficiency | Urine (fresh) | Sulphite dipstick |
Purine studies | ||
Purine disorders | Urine | Purine studies |
Peroxisomal disorders | Plasma | Very long-chain fatty acids |
↵* Effective treatment available.
CSF, cerebrospinal fluid; GLUT-1, glucose transporter 1.