Editing Frameshift mutation (section)

===Smith–Magenis syndrome===

[[Smith–Magenis syndrome]] (SMS) is a complex [[syndrome]] involving intellectual disabilities, sleep disturbance, behavioural problems, and a variety of craniofacial, skeletal, and visceral anomalies. The majority of SMS cases harbor an ~3.5 Mb common deletion that encompasses the retinoic acid induced-1 (''[[RAI1]]'') gene. Other cases illustrate variability in the SMS [[phenotype]] not previously shown for RAI1 mutation, including hearing loss, self-abusive behaviours, and mild global delays. Sequencing of RAI1 revealed mutation of a heptamericC-tract (CCCCCCC) in exon 3 resulting in frameshift mutations. Of the seven reported frameshift mutations occurring in poly C-tracts in RAI1, four cases (~57%) occur at this heptameric C-tract. The results indicate that this heptameric C-tract is a preferential [[recombination hotspot]] insertion/deletions (SNindels) and therefore a primary target for analysis in patients suspected for mutations in RAI1.<ref>{{cite journal|last=Truong|first=Hoa T|author2=Dudding, Tracy|author3= Blanchard, Christopher L.|author4= Elsea, Sarah H|title=Frameshift mutation hotspot identified in Smith-Magenis syndrome: case report and review of literature|journal=BMC Medical Genetics|volume=11|issue=1|page=142|doi=10.1186/1471-2350-11-142 |pmid=20932317 |pmc=2964533 |year=2010 |doi-access=free }}</ref>