Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

FPORC
91763
HTT
83302
Rodrigues HE, et al: Pharmacogenetics of antidepressants medication intolerance. Am J Psychiatry
2003;160(10):1830-1835 3. Arranz MJ, Murno J, Birkett J, et al: Pharmacogenetic prediction of clozapine
response. Lancet 2000;355(9215):1615-1616 4. Reynolds GP, Zhang ZJ, Zhang XB: Polymorphism of the
promoter region of the serotonin 5-HT2C receptor gene and clozapine-induced weight gain. Am J
Psychiatry 2003;160:677-679 5. Segman RH, Heresco-Levy U, Finkel B, et al: Association between the
serotonin 2A receptor gene and tardive dyskinesia in chronic schizophrenia. Mol Psychiatry
2001;6(2):225-229 6. Segman RH, Heresco-Levy U, Finkel B, et al: Association between the serotonin
2C receptor gene and tardive dyskinesia in chronic schizophrenia: additive contribution of 5-HT2Cser and
DRD3gly alleles to susceptibility. Psychopharmacology 2000;152(4):408-413 7. Choi MJ, Kang RH,
Ham BJ, et al: Serotonin receptor 2A gene polymorphism (-1438A->G) and short-term treatment response
to citalopram. Neuropsychobiology 2005;52:155-162 8. McMahon FJ, Buervenich S, Charney D, et al:
Variation in the gene encoding the serotonin 2A receptor is associated with outcome of antidepressant
treatment. Am J Hum Genet 2006;78:804-814
Serotonin Release Assay, Unfractionated Heparin
Reference Values:
An interpretive comment included with results.
Test Performed by: BloodCenter of Wisconsin
638 N. 18th Street
Milwaukee, WI 53233-2121
Serotonin Transporter Genotype, Blood
Clinical Information: Serotonin (5-hydroxytryptamine; 5-HT) is a neurotransmitter. The serotonin
transporter (5-HTT) modulates neurotransmission by facilitating removal of serotonin from the synapse
of serotonergic neurons, resulting in serotonin reuptake into the presynaptic terminus. Other
designations for 5-HTT are SLC6A4 (solute carrier family 6 [neurotransmitter transporter, serotonin],
member 4), hSERT, OCD1, SERT, sodium-dependent serotonin transporter, and 5-HT transporter.
Selective serotonin reuptake inhibitors (SSRIs) block the action of the serotonin transporter and are used
to treat depression and other neuropsychiatric disorders. Examples of SSRIs are fluoxetine (Prozac),
fluvoxamine (Luvox), escitalopram oxalate (Lexapro), sertraline (Zoloft), citalopram (Celexa), and
paroxetine (Paxil, Paxil CR). The 5-HTT gene is located at 17q11.1-q12 and is composed of 14 exons
spanning 31 kb. A 44-base pair promoter insertion/deletion polymorphism called LPR, or linked
polymorphic region, produces alleles described as long or short. The short allele is dominant and results
in decreased concentration of the transporter protein and a poorer response to stressful events. While
individuals homozygous for the long allele (l/l) may demonstrate response to SSRI therapy in 3 to 4
weeks, individuals with the short allele (l/s or s/s) may respond to SSRI therapy more slowly, taking up
to 12 weeks.
Useful For: Evaluating patients who have failed therapy with selective serotonin reuptake inhibitors
(SSRIs) Evaluating patients with treatment-resistant depression Predicting response time to
improvement with SSRIs Identifying patients who might respond favorably to a class of antidepressants
other than SSRI. Identifying patients who have diminished amounts of the serotonin transporter and,
hence, an altered response to SSRI therapeutics
Interpretation: The normal (wildtype) allele yields a long product (l/l). The variant is short/short
(s/s). Heterozygotes have a l/s genotype. Individuals homozygous for the long allele (l/l) may respond
more rapidly to selective serotonin reuptake inhibitors (SSRI) therapy. Individuals homozygous for the
short allele (s/s) may respond more slowly to SSRI therapy and may benefit from a longer trial before
considering switching to another antidepressant. Even 1 copy of the short allele (heterozygous)
decreases the amount of the transporter protein present, increasing the time to response.
Reference Values:
An interpretive report will be provided.
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