Pharmacogenomics_Paediatric

Gene: CYP2C9

25099164
If CYP2C9 IM, consider 25% reduction starting dose (moderate recommendation).
If CYP2C9 PM, consider 50% reduction starting dose phenytoin (strong recommendation).

Created: 21 Sep 2020, 1:01 a.m. | Last Modified: 21 Sep 2020, 1:18 a.m.

Panel Version: 0.50

(32189324)
Note poor metabolizer status has increased exposure (and possible sensitivity) to certain NSAIDs.
"Alternative therapies not primarily metabolized by CYP2C9 include aspirin, ketorolac, naproxen, and sulindac. Selection of therapy will depend on individual patient treatment goals and risks for toxicity."
Probably not sufficient evidence to test for CYP2C9 alone, however if information available may be worth noting.

Created: 14 Aug 2020, 1:28 a.m. | Last Modified: 14 Aug 2020, 1:28 a.m.

Panel Version: 0.33

In vivo, metabolic activity over 1y age is same as adults (18406467).

Created: 14 Aug 2020, 12:33 a.m. | Last Modified: 14 Aug 2020, 12:33 a.m.

Panel Version: 0.33

Phenotypes
Phenytoin metabolism - increased risk toxicities

Publications

• 18406467
• 25099164

Green List (high evidence)

Activity levels of CYP2C9 are at 1-2% of adult values in the fetus during the first trimester. These levels gradually increase to 30% of adult values at term. There is a high variability in these levels during the first 5 months of life, with levels eventually approaching adult values somewhere between 5 months and 2 years of age.

Created: 1 Aug 2020, 1:52 a.m. | Last Modified: 1 Aug 2020, 1:52 a.m.

Panel Version: 0.19

Sources: Expert list

Created: 31 Jul 2020, 10:12 a.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Warfarin sensitivity, MIM# 122700; Phenytoin

Publications

• 25099164
• 21900891
• 28198005