The major features of Smith-Magenis syndrome include mild to moderate intellectual disability, delayed speech and language skills, distinctive facial features, sleep disturbances, and behavioral problems.
Most people with Smith-Magenis syndrome have a broad, square-shaped face with deep-set eyes, full cheeks, and a prominent lower jaw. The middle of the face and the bridge of the nose often appear flattened. The mouth tends to turn downward with a full, outward-curving upper lip. These facial differences can be subtle in early childhood, but they usually become more distinctive in later childhood and adulthood. Dental abnormalities are also common in affected individuals.
Disrupted sleep patterns are characteristic of Smith-Magenis syndrome, typically beginning early in life. Affected people may be very sleepy during the day, but have trouble falling asleep and awaken several times each night.
People with Smith-Magenis syndrome have affectionate, engaging personalities, but most also have behavioral problems. These include frequent temper tantrums and outbursts, aggression, anxiety, impulsiveness, and difficulty paying attention. Self-injury, including biting, hitting, head banging, and skin picking, is very common. Repetitive self-hugging is a behavioral trait that may be unique to Smith-Magenis syndrome. People with this condition also compulsively lick their fingers and flip pages of books and magazines (a behavior known as 'lick and flip').
Other signs and symptoms of Smith-Magenis syndrome include short stature, abnormal curvature of the spine (scoliosis), reduced sensitivity to pain and temperature, and a hoarse voice. Some people with this disorder have ear abnormalities that lead to hearing loss. Affected individuals may have eye abnormalities that cause nearsightedness (myopia) and other vision problems. Although less common, heart and kidney defects also have been reported in people with Smith-Magenis syndrome.
The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
|Signs and Symptoms||Approximate number of patients (when available)|
|Attention deficit hyperactivity disorder||90%|
|Deeply set eye||90%|
|Depressed nasal bridge||90%|
|Neurological speech impairment||90%|
|Reduced number of teeth||90%|
|Tented upper lip vermilion||90%|
|Upslanted palpebral fissure||90%|
|Abnormality of the larynx||75%|
|Delayed speech and language development||75%|
|Everted upper lip vermilion||75%|
|Morphological abnormality of the middle ear||75%|
|Abnormal form of the vertebral bodies||50%|
|Abnormality of the outer ear||50%|
|Abnormality of the tongue||50%|
|Abnormality of the tracheobronchial system||50%|
|Aplasia/Hypoplasia of the corpus callosum||50%|
|Clinodactyly of the 5th finger||50%|
|Conductive hearing impairment||50%|
|Impaired pain sensation||50%|
|Prenatal movement abnormality||50%|
|Wide nasal bridge||50%|
|Abnormality of cardiovascular system morphology||33%|
|Abnormal localization of kidney||7.5%|
|Abnormality of the forearm||7.5%|
|Abnormality of the genital system||7.5%|
|Abnormality of the ureter||7.5%|
|Cleft upper lip||7.5%|
|Limitation of joint mobility||7.5%|
|Abnormal renal morphology||-|
|Autosomal dominant inheritance||-|
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.
The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
2016 8th SMS Research Symposium
Thursday, February 4, 2016 -
Friday, February 5, 2016
Location: Baylor College of Medicine and Texas Children’s Hospital, Houston, TX
Description: PRISMS, Inc (Parents and Researchers Interested in Smith-Magenis Syndrome) invites research and medical professionals to PRISMS 8th SMS Research Symposium at Baylor College of Medicine and Texas Childrens Hospital in Houston, TX on February 4-5, 2016. Registration is now open. There is no registration fee for this PRISMS-sponsored event. Registration is limited to members of the research professional community. PRISMS is now accepting abstracts! Questions should be directed to Emily Fields, Executive Director, firstname.lastname@example.org.
Co-funding Institute(s): Other
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Is it true that Smith-Magenis syndrome become more difficult to diagnose through genetic testing if the child is older than 24 months? See answer
My adult son was recently diagnosed with Smith-Magenis. My son and others seem to crave caffeine and will go to all kinds of lengths to get it. Do people with Smith-Magenis crave caffeine? See answer
Can children with Smith-Magenis syndrome be potty-trained? Can they learn to talk? What are their learning capabilities? See answer