Abstract
As a multisystemic congenital mental retardation disorder/anomaly, Smith–Magenis syndrome
(SMS) is commonly aroused from de novo interstitial deletion of the 17p11.2 chromosome.
The deletion of this chromosome results with haploinsufficiency for the retinoic acid-induced
1 (RAI1) gene. In this article, we present three cases, who were diagnosed with SMS with
mental retardation and behavioral problems such as self-hugging and sleeping disturbances.
During the evaluation of the patients, it has been found that there was a 3.4-Mb deletion
in the 17p11.2 chromosome region of these patients. This deletion includes RAI1 that is a critically involved gene in SMS.
Keywords
Smith–Magenis syndrome - chromosome 17p11.2 deletion - sleep disturbance