Overview: Smith-Magenis Syndrome

*I have borrowed heavily from Taylor’s mom’s website as well as PRISMS for this page.

Smith-Magenis is a rare syndrome that only 600 people in the world have been diagnosed with – but many more probably have. It is caused by the missing piece of genetic material from chromosome 17p11.2 or from a mutation of the RAI1 gene. This disorder is generally only detected through a FISH analysis (test). Or from a Sequence Analysis which detects the sequence alterations in the RAI1 gene. Micro array CGH tests may also find SMS.

Before I delve into the clinical components of Smith-Magenis Syndrome, I want to point out some of their attributes. Individuals with SMS are sweet, affectionate, helpful, joyful, enthusiastic, compassionate, determined, resilient, couarageous, fun-loving, comical, amazing people with beautiful souls. And provide love to all those around them like no one else can! Their smiles fill rooms with sunshine and their laughter fills rooms with happiness. They are devoted, faithful, sincere, and have unconditional love. They are non-judgemental they only see abilities in others. Their loving ways are immeasurable! They are living with Smith-Magenis Syndrome but they are not their syndrome.

The NIH paper describing SMS. (not a fun read.)


Common Characteristics of SMS

Facial features include:

A flat mid-section of the forehead and bridge of nose, tented upper lip and down-turned mouth. prominent and usually rosy cheeks (cherub-like as infants), broad and square shaped face, prominent jaw (usually more noticeable in older children and adults), deep set and close-spaced eyes, dark eyebrows that meet in the middle, flat and wide or disproportioned head.

Common features present in 50-75% of individuals with SMS

* :Sleep disturbance (i.e. frequent nighttime awakenings, sleepiness in day/frequent napping, early morning awake times)
* Inverted circadian rhythm of melatonin
* Hypotonia (low muscle tone)
* Short stature
* Small, short and wide hands and feet
* Scoliosis
* Hearing loss
* Flat feet
* Over responsive reflexes
* Open mouth posture, frequent drooling
* Ocular abnormalities
* Middle ear abnormalities (chronic ear infections)
* Deep, hoarse voice, or hyper nasal speech
* Dental anomalies
* Decreased sensitivity to pain
* Oral-sensory motor dysfunction (poor suck/swallow, decreased tongue strength & movement, and aversion to textures)
* Wide gait
* Eye problems
* Frequent constipation
* Hypercholesterolemia/hypertriglyceridemia
* Abnormal EEG without seizures
* Signs of peripheal neuropathy
* Mild enlargement of the ventricular system in the brain
* Tracheobronchial problems.
* Speech delay and articulation difficulty (little vocalization in infancy)
* Velopharyngeal insufficiency (improper closing of soft palate muscle)
* Teeth Grinding
* Rocking motion

Developmental Features present in 75% of individuals with SMS

* Cognitive impairment/developmental delays
* Sensory integration issues
* Self injurious behaviors (i.e. head banging, hand biting, picking at skin and sores, inserting foreign object into ears and nose or other body orifices, pulling off fingernails and toenails (older age)
* Generalized complacency/lethargy (infancy)
* Mouthing objects or hands that persists beyond early childhood
* Maladaptive behaviors: (i.e. hyperactivity, explosive outbursts, lack of impulse control, prolonged tantrums, attention seeking (especially from adults), easy to be excited and easy to be distracted, aggressive, destructive)
* Repetitive behaviors (i.e. hand squeezing or arm hugging when excited, quickly flipping pages of books/magazines (“lick and flick”)

There are other less common features as well.


I unabashedly stole the following from Taylor’s website. I couldn’t have written this better myself, so I figured I needn’t change anything but the names for the most part. Hoang and I agree 100%.

We feel very lucky that Damian has few medical issues at this point. And though we can’t prevent other medical conditions that occur, we do keep up to date with doctor appointments to stay on top of her health. We selfishly hope (as most parents do) for his sake that he does not get scoliosis or peripheal neuropathy.

Through contact with several parents we are reminded as to how lucky we are at this point. And we do not take it for granted. For many children with Smith-Magenis, they have endured several more medical challenges than us. Several are fed through feeding tubes, several have visual problems, several have had far too many ear infections and surgeries to put tubes in their ears (many have had to have this surgery repeated several times – Damian only once at this point). Many have had their adenoids and tonsils out at young ages. Many have low immune systems. Several children have difficulty enunciating because of low muscle tone/weak vocal chords. So, sign language is important. Many have heart defects and have had to have heart surgeries at a young age.

There are several parents of children with SMS who have had many medical scares. And on top of it all, have had their children misdiagnosed. Misdiagnosed with diseases that would have given their children short life spans. And for others, doctors dismissed the parents concerns all together.

As a parent it is heart wrenching to watch your child have several obstacles/challenges that they recognize to some degree. There are too many children who have felt it necessary to apologize for their Smith-Magenis Syndrome. And that breaks your heart! They realize something isn’t quite right and as parents you want to fix it (for their sake). They should never have to feel sorry for things they cannot control. So, we will continue to support medical research to find a cure for these beautiful people living with Smith-Magenis.

Until then, we live in the moment. We cherish EVERY triumph and all the endless love that we enjoy from our children. And we find our way through the rough patches and medical scares! We will cry tears of happiness for little things that other parents don’t really notice or appreciate.

We are thankful for those researches who have taken a special interest in finding a cure for Smith-Magenis Syndrome. There are very few of those researchers out there. So, those that have taken the time are people that we truly appreciate!

4 responses to “Overview: Smith-Magenis Syndrome”

  1. chrissy says:

    we beleive our son tyler has sms his genetics doctor strongly agrees but his fish was neg so he is beleived to have the other deletion but theres only one lab that test for it i belive its called rai1 deletion i think any web sites or parents stories are great for two reason one i actually found this disorder on the web and brought it to the genetics doctor after many miss diognosis and finding out he has white matter missing in his brain along with many other problems number two is everytime i tell somone about this they have never hurd of it and i thought untill recently that there was knowone else with tylers complicated problems so thanks to all who are getting the word out

  2. derek says:

    wow, very interesting

  3. Bella says:

    OMG I am doing a project on this syndrome and this was very helpful! Thank-you very much! Also that little boy is so cute!

  4. karina says:

    i had a project and found site very helpful,good info and understandable thank you very much for the help

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