Which are the symptoms of Smith Magenis Syndrome?

Smith-Magenis Syndrome (SMS) is a rare genetic disorder that affects various aspects of an individual's development and behavior. It is caused by the deletion or mutation of a specific region of chromosome 17, known as 17p11.2. This condition is characterized by a distinct set of physical, cognitive, and behavioral features.

Physical Symptoms:

• Distinct facial features: Individuals with SMS often have a broad forehead, deep-set eyes, a flattened mid-face, a short nose, and a prominent lower jaw.


• Delayed growth: Children with SMS may experience growth delays, resulting in shorter stature compared to their peers.


• Sleep disturbances: Sleep problems are common in individuals with SMS, including difficulty falling asleep, frequent awakenings, and abnormal sleep patterns.


• Speech and language difficulties: Many individuals with SMS have delayed speech development, limited vocabulary, and articulation problems.


• Hearing loss: Sensorineural hearing loss is prevalent in individuals with SMS, which may require the use of hearing aids.


• Recurrent infections: Individuals with SMS may be more susceptible to respiratory and ear infections.


• Orthopedic abnormalities: Some individuals may have skeletal abnormalities, such as scoliosis or joint contractures.

Cognitive and Behavioral Symptoms:

• Intellectual disability: The majority of individuals with SMS have mild to moderate intellectual disability, with varying degrees of cognitive impairment.


• Behavioral problems: Individuals with SMS often exhibit challenging behaviors, including self-injury, aggression, impulsivity, and attention-deficit/hyperactivity disorder (ADHD)-like symptoms.


• Repetitive behaviors: Stereotypic movements, such as hand-flapping or body-rocking, are common in individuals with SMS.


• Hyperactivity: Many individuals with SMS have high levels of energy and restlessness.


• Anxiety and mood disorders: Anxiety, depression, and mood swings can be present in individuals with SMS.


• Sensory processing issues: Individuals with SMS may have sensory sensitivities or difficulties processing sensory information.


• Self-injurious behaviors: Some individuals with SMS engage in self-harming behaviors, such as head-banging or biting themselves.

Other Features:

• Distinct behavioral phenotype: The combination of cognitive and behavioral features in SMS creates a unique behavioral profile that can help in diagnosing the syndrome.


• Delayed motor skills: Children with SMS may have delays in acquiring motor skills, such as sitting, crawling, or walking.


• Feeding difficulties: Infants with SMS may experience difficulties with feeding, including poor sucking or swallowing.


• Eye abnormalities: Some individuals may have vision problems, such as strabismus (crossed eyes) or refractive errors.


• Heart defects: A small percentage of individuals with SMS may have congenital heart defects.

It is important to note that not all individuals with SMS will exhibit every symptom mentioned above, and the severity of symptoms can vary widely. Early diagnosis and intervention, including speech therapy, occupational therapy, and behavioral interventions, can greatly improve the quality of life for individuals with Smith-Magenis Syndrome.