Test Directory
5405 MTHFR Mutations C677T / A1298C
Specimen Type
Specimen Stability
Reference Range
Whole blood-Lavender top tube
8 days 2-8°C
Not Detected
Specimen Requirements
5 mL Whole Blood
Method
PCR-Invader
Schedule
Tues, Thurs, Sat
Turn-Around Time
2-3 Days
Instructions/Notes
Clinical Utility
Common mutations in the methylenetetrahydrofolate reductase (MTHFR) gene (C677T) and (A1298C) produce an enzyme with decreased activity which can result in a mild elevation of plasma homocysteine levels. Only individuals homozygous for C677T mutation or compound heterozygous for the C667T/A1298C mutations have significantly elevated plasma homocysteine levels. Heterozygotes for A1298C alone have no significant increase of plasma homocysteine levels. Triple variants or compound heterozygous and homozygous variants are rare. Double homozygotes have not been reported in the population. Mild elevation of plasma homocysteine levels is associated with an increased risk of atherosclerosis and thrombosis. In addition, hyperhomocysteinemia is found in women who have experienced two or more early pregnancy losses, placental infarction, and fetal growth retardation; however, MTHFR mutation as a cause of early pregnancy loss is still controversial. Elevated homocysteine levels can be treated by nutritional supplements. Other family members may benefit from DNA testing to revise the relative risk of atherosclerosis and thrombosis.
CPT Codes
83891, 83892, 83898x2, 83896x6, 83903, 83908, 83912; NOTE: New 2013 CPT: 81291
