Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is typified by a microdeletion of chromosome band 17p11.2. Fluorescence in situ hybridization (FISH) analysis of a patient's chromsomes is shown. The green control probe shows that an unrelated region of chromosome 17 is present in both chromosomes 17. The red probe, which detects the 17p11.2 region commonly deleted in SMS, only fluoresces on a single chromosome. This finding strongly supports the diagnosis of SMS.