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Test ID HTTO Serotonin Transporter Genotype, Saliva

Useful For

Qualifying participants for clinical trials

 

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 nonselective antidepressants

 

Identifying patients who have diminished amounts of the serotonin transporter and, hence, an altered response to SSRI therapeutics

 

Genotyping patients who prefer not to have venipuncture done

Method Name

Polymerase Chain Reaction (PCR) Followed by Sizing Analysis

(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)

Reporting Name

Serotonin Transporter (LPR), Saliva

Specimen Type

Saliva

Multiple saliva genotype tests can be performed on a single specimen after a single extraction. See Multiple Saliva Genotype Tests in Special Instructions for a list of tests that can be ordered together.

 

Container/Tube: Oragene DNA Self-Collection Kit (Supply T651: fees apply)

Specimen Volume: Full tube

Collection Instructions:

1. Fill tube to line.

2. Send specimen in original container per kit instructions.

Forms: New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Saliva Ambient

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 include 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.

Reference Values

An interpretive report will be provided.

Cautions

Note that in patients who have received heterologous blood transfusions before a saliva sample was acquired, the saliva samples may contain donor DNA. Return to recipient genotype usually occurs after 6 weeks. Similarly, saliva samples obtained from patients after allogeneic blood or marrow transplantation can contain donor DNA. In both cases, this may result in genotyping results that reflect the genotype of the recipient, the donor, or a blend of the donor and recipient. Results obtained under these circumstances may not accurately reflect the recipient’s genotype.

 

The test measures only the 5-hydroxytryptamine transporter (5-HTT)(linked polymorphic region) polymorphism and will not indicate the presence of any other polymorphism. A mutation occurring at the site of PCR primer annealing could lead to a heterozygote being incorrectly labeled as a homozygote.

Day(s) Performed

Monday, Thursday; 8 a.m.

Report Available

1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81479 -Unlisted molecular pathology procedure

NY State Approved

Conditional