- Brachycephaly with a typical craniofacial appearance (midface hypoplasia, characteristic mouth with a ‘cupid’s bow’ shape, prognathism)
- Ocular abnormalities (myopia and strabismus, iris anomalies)
- Speech delay with or without hearing loss
- Hoarse, deep voice
- Short stature with a history of failure to thrive
- Brachydactyly
- Peripheral neuropathy (pes cavus or pes planus, depressed deep tendon reflexes), and
- Scoliosis
- Aggression
- Self-injurious behaviours
- Low sensitivity to pain
- Temper tantrums
- Impulsivity
- Repetitive behaviour
- Hyperactivity with attention deficit
Figure 1. Phenotypic Features of Smith Magenis Syndrome4
![Figure-1_A](https://flynnforum.com/wp-content/uploads/2022/09/Figure-1_A.jpg)
![Figure-1_B](https://flynnforum.com/wp-content/uploads/2022/09/Figure-1_B.jpg)
![Figure-1_C](https://flynnforum.com/wp-content/uploads/2022/09/Figure-1_C.jpg)
![Figure-1_D](https://flynnforum.com/wp-content/uploads/2022/09/Figure-1_D.jpg)
![Figure-1_E](https://flynnforum.com/wp-content/uploads/2022/09/Figure-1_E.jpg)
A. SMS patient with sleep disturbance, illustrating commonly observed "sleep attacks".
B. Craniofacial anomalies can include midface hypoplasia and tented upper lip in SMS.
C. Self-injurious behaviours like pulling out of fingernails and/or toenails are unique to SMS.
D. Stereotypical behaviour like self-hugging in SMS patient, typically observed during times of excitement or happiness.
E. Obesity is frequently observed in persons with SMS.
References:
3. De Leersnyder, H. 2006. ‘Inverted rhythm of melatonin secretion in Smith-Magenis syndrome: from symptoms to treatment’, TRENDS in Endocrinology and Metabolism. Volume 17, Issue 7, 291-298
4. Chen, Li. et. al. 2015. ‘Smith-Magenis syndrome and its circadian influence on development, behaviour, and obesity – own experience’, Developmental Period Medicine. Volume 19, Issue 2, 149-56