3p deletion syndrome is a condition that results from a chromosomal change in which a small piece of chromosome 3 is deleted in each cell. The deletion occurs at the end of the short (p) arm of the chromosome. This chromosomal change often leads to intellectual disability, developmental delay, and abnormal physical features.
Individuals with 3p deletion syndrome typically have severe to profound intellectual disability. Most have delayed development of language skills as well as motor skills such as crawling and walking. While affected individuals learn to walk in childhood, their language ability usually remains limited. Some individuals with 3p deletion syndrome have obsessive-compulsive disorder (OCD) or features of autism spectrum disorders, which are conditions characterized by impaired communication and social interaction.
The physical signs and symptoms of 3p deletion syndrome vary greatly. Many affected individuals have slow growth, an abnormally small head (), a small jaw (), droopy eyelids (), malformed ears or nose, and widely spaced eyes (). Other frequent features include skin folds covering the inner corner of the eyes (), extra fingers or toes (polydactyly), and an opening in the roof of the mouth (). Additionally, individuals with 3p deletion syndrome may have seizures, weak muscle tone (hypotonia), intestinal abnormalities, or congenital heart defects.