SMN1 Dosage Spinal Muscular Atrophy Carrier

Label Mnemonic:	SMACT
Epic code:	LAB4075
Downtime form:	Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Commercial Mailout Laboratory
6240-8 RCP
356-8593

Specimen(s):

Whole Blood

Collection Medium:

	or
Pink top tube 6 mL (K2-EDTA)	or	Lavender top tube 3 mL (EDTA)

Minimum:

Adult Minimum: 6 mL whole blood in pink top tube
Pediatric Minimum: 2-3 mL whole blood in lavender top tube

Delivery Instructions:

Deliver to laboratory immediately after collection.

Turn Around Time:

14 days upon receipt at reference laboratory

Interpretive Data:

The survival motor neuron 1 (SMN1) gene has been shown to be homozygously deleted in approximately 95% of the SMA patients (0 SMN1 copy). The majority of the other 5% of affected patients are compound heterozygotes, possessing a single SMN1 deletion (1 SMN1 copy) and a smaller intragenic type of mutation within the SMN1 gene. Loss of SMN1 is essential to the pathogenesis of the disease, while the disease severity is primarily correlated with the number of copies of SMN2. Most type 1 patients have two copies of SMN2(and occasionally one copy). Three copies are common in SMA type II patients, and type III patients often have 3 or 4 copies of SMN2.

CPT Code:

81329