Pharmacogenetic testing for Suxamethonium (Succinylcholine)

Request a test for your patient
The tests can be requested only by Registered clinicians. If you are a patient, you could contact your consulting clinician to refer you for genetic screening.

Recommendation and Drug Label warning
The US FDA-approved label warns that individuals who are carriers of the atypical variant of the plasma cholinesterase gene (BCHE) are at risk of prolonged apnea if administered succinylcholine. The US FDA-approved label contraindicates succinylcholine for individuals carrying one of many genetic variants known to increase the risk of adverse side effect.

Information Brochure
Suxamethonium (Succinylcholine) is an adjunct to general anesthesia, to facilitate tracheal intubation, and to provide skeletal muscle relaxation during surgery or mechanical ventilation. Succinylcholine, is a fast-acting depolarising muscle relaxant and is widely used in clinical settings. Succinylcholine is an analog of the neurotransmitter acetylcholine. The molecule binds non-competitively and therefore the binding cannot be reversed and recovery is spontaneous.

The molecule is metabolised by the BChE enzyme encoded by the BCHE gene. Patients with normal BCHE gene hydrolyze 90% of the injected drug dose before it reaches nerve synapse in the muscle. In contrast, subjects with an abnormal BChE gene results in a huge overdose leading to prolonged muscle paralysis, a serious and potentially lethal adverse drug response. Apart from succinylcholine containing drugs Quelicin & Anectine, the gene also is involved in metabolism of mivacurium, ester local anesthetics particularly chloroprocaine. 

The prevalence of BCHE deficiency varies with population as well as ethnic subgroups. The incidence is approximately 1 in 100,000 individuals of European or American descent being homozygous for the variant, whereas some ethnic subgroups, including the Vysya community of India have a high prevalence of approximately 4%. 

Genetic variants associated with BChE deficiency
A number of genetic variants are associated with BChE deficiency. ClinVar, a comprehensive resource for genetic variants associated with human traits lists over 31 pathogenic variants. The prevalent genetic variants include: rs104893684; rs28933390; rs12198557; rs28933389; rs121918558; rs201820739; rs1799807  and rs121918556  in BCHE gene.
Referring your patient for Pharmacogenetic testing of BChE gene
Pharmacogenetic testing in research mode for succinylcholine is available through the GOMED programme for the prevalent variant rs104893684 in South Asian Populations. Additional variants listed above may be tested on request of the investigator.

Documentation required 
1) Genomic test request 
Please write a referral on your letterhead regarding the referral and the test you would be requesting.
2) Consent forms (one each for each patient) 
The consent forms for genomic analysis needs to be signed individually by each member (or parent/guardian in case the person is a minor). Each consent needs to be counter-signed by the investigator.
Consignment information/declaration
Since you would be posting out blood samples, you would require to attach a declaration which should be signed/stamped and given to the courier/postage department for processing your courier. 
Referring us a case for genetic testing
Please follow the step-wise guidelines as described here for referring a case. Please follow the instructions for packing and sending us samples.
Vinod Scaria,
May 30, 2017, 5:16 AM
Vinod Scaria,
May 25, 2017, 12:40 AM