Chromosome 22 microdeletion correlates with different phenotypes. Prevalence is estimated between 1/2000-1/4000 newborns. Deletion arise di novo in almost 90% of the cases and the pattern of transmission is autosomal dominant. The most frequently described features are: orofacial abnormalities, heart defects, inmunological alterations, intelectual disabilities, attention deficit and psychiatric problems.

The prognosis is variable. The mortality rate is relatively low in infants (around 4%), however in adults it is higher than the rest of adult population.

To show, through the follow-up of a case report, the diagnostic difficulties when mental disorder and intellectual disability coexist.

Case report of a patient followed up in an ambulatory mental health clinic after discharge of an acute psychiatric unit.

An accurate diagnosis of primary mental disorders in a person with intellectual disability requires knowledge of the degree of intellectual disability, as well as knowledge of his verbal and communicative skills and comorbid medical diseases.

A combination of multiple dysmorphic features, anatomical abnormalities (primarily cardiac and gastrointestinal), stunting, endocrine problems and intellectual disability suggest chromosomal abnormalities.

Behavioral phenotypes are cognition and behavior patterns that are more likely to appear in a specific disease. They give us clues about the complex nature of interactions between genes and behavior.