Neurodevelopmental disorders are a group of pathologies with increased frequency in pediatric practice. During the last decade, genetic studies such as CGH arrays have aided in the search for genetic gains or losses that may help explain the symptoms.

There are CNVs, like the 15q11.2 microdeletion between BP1 and BP2, that although considered pathological, may present incomplete penetrance and variable expression, both of which add difficulty to the already complicated task of genetic counseling to the family members.

Hereby we present cases of three patients with similar phenotypes in which microdeletion of 15q11.2 was detected.