Smith-Magenis syndrome

What is it?

Smith-Magenis Syndrome is a genetic disorder that occurs due to an interstitial deletion of the short arm of chromosome 17, the size of the deletion is usually 2 to 9 MB, the most common is about 4 MB. There are several genes in this chromosomal part whose function is not yet fully understood, it seems that one of the genes responsible for most of the characteristics present in patients with Smith-Magenis syndrome is RAI1, in fact, some patients with clinical symptoms have also been described Smith-Magenis syndrome with a mutation in the RAI1 gene.

Causes and risk factors

The frequency is about 1/25000 births.
The syndrome is caused by a deletion of the chromosomal portion of the short arm of chromosome 17p11.2; this deletion is usually a sporadic event not inherited from the parents.

Which are the symptoms?

  • features of children's faces: the face of a cherub with chubby cheeks, median facial hypoplasia, a depressed bridge of the nose and a curved cupid's mouth; in adults, coarse facies, thick eyebrows, sinophris and prognathism.
  • obesity
  • eye abnormalities (85%).
  • delayed speech development (96%), sometimes associated with hearing loss
  • low growth (78%);
  • brachydactyly
  • peripheral neuropathy (flat feet or hollow feet, insensitivity to pain) (75%)
  • moderate / severe mental retardation (100%)
  • behavioral problems (sleep disturbance; stereotypes, self-aggression)
  • voice abnormalities
  • malformations of the urinary tract
  • scoliosis
  • malformations of the heart

How is it treated?

There is no specific therapy for this syndrome, but it is based on the treatment of individual symptoms.

To help develop speech and correct pronunciation of words, it would be helpful to see a speech therapist.

Evaluation of sleep at a clinical sleep monitoring center is recommended, and the use of melatonin in these patients is considered beneficial.

ENT examinations for possible changes in the larynx and hearing problems,

Ophthalmic assessment

Where do we treat it?

Within the San Donato Group, you can find Smith-Magenis syndrome specialists at these departments:

Are you interested in receiving the treatment?

Contact us and we will take care of you.