Smith-Magenis Syndrome (SMS)

Smith-Magenis Syndrome (SMS) is characterized by facial dysmorphism, behavioral problems, sleep disturbances, growth retardation and moderate mental retardation. Brachycephaly, mid-facial hypoplasia with broad flat midface, broad nasal bridge, and prognathism are classical facial features. Cognitive, psychomotor, and speech delays are common. Neurobehavioral features become more pronounced with age and can include hyperactivity, temper tantrums, attention-seeking, self-hugging, self-injurious behaviors, and sleep disturbances. About 40% of patients with the 17p11.2 deletion have structural or functional congenital heart defects. Hoarse voice, hearing loss, and eye abnormalities are frequently present as well. Hypercholesterolemia has been reported in 70% of affected patients.

Tests Available

Forms and Documents

Test Details

  • Confirmation of clinical diagnosis
  • Recurrence risk estimation


3 weeks
2-5 mL Blood - Lavender Top Tube
Buccal Swabs

*Reporting times are typical, but could be extended in situations outside GeneDx's reasonable control.


81405x1, 81479x1
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**The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


  1. Nakamine, A. et al., Duplication of 17(p11.2p11.2) in a male child with autism and severe language delay. Am J Med Genet. 146A(5):636-643, 2008
  2. Dr. Sarah Elsea, personal communication, 2005
  3. Girirajan, S. et al., RAI1 variations in Smith-Magenis syndrome patients without 17p11.2 deletions. J Med Genet. 42: 820-28, 2005
  4. Bi, W. et al., Mutations of RAI1, a PHD-containing protein, in non-deletion patients with Smith-Magenis syndrome. Hum Genet. 115: 515-24, 2004
  5. Slager, al., Mutations in RAI1 associated with Smith-Magenis syndrome. Nat Genet. 33: 466-68 2003
  6. Girirajan, S. et al., Genotype-phenotype correlation in Smith-Magenis syndrome: Evidence that multiple genes in 17p11.2 contribute to the clinical spectrum. Genet Med. 8: 417-27, 2006