| Dihydropteridine
reductase (DHPR) activity (Guthrie card)
This
test is essential in every newborn with even mild hyperphenylalaninemia,
as well as in older patients
with neurological symptoms.
Blood collection for DHPR activity
Collect
2-4 drops of blood on a Guthrie card. Protect the card
from humidity. DHPR activity in RBC (reference values)
| Age |
DHPR(RBC) |
| |
µU/g Hb |
| Newborns |
2.0µ-5.0 |
| Fetus (16-20 wg) |
2.3-3.8 |
REFERENCES
- Arai N, Narisawa K, Hayakawa H, Tada K. Hyperphenylalaninemia
due to dihydropteridine reductase deficiency: diagnosis
by enzyme assays on dried blood spots. Pediatrics 1982;70:426-430.
- Bracco G, Iavarone A, Pagliardini S, Levis
F, Guardamagna O, Ferraris S, Ponzone A. Dihydropteridine
reductase activity
in fetal tissues. In: Curtius HC, Blau N, Levine RA,
eds. Unconjugated Pterins and Related Biogenic Amines.
Berlin,
New York: de Gruyter, 1987: 265-273.
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