1p36 deletion syndrome
is a chromosome disorder that typically causes severe intellectual disability. Most affected individuals do not speak, or speak only a few words. They may have temper tantrums, bite themselves, or exhibit other behavior problems. Most have structural abnormalities of the brain, and seizures occur in more than half of individuals with this disorder. Affected individuals usually have weak muscle tone (hypotonia) and swallowing difficulties (dysphagia). Other features include a small head that is unusually short and wide; vision and hearing problems; abnormalities of the skeleton, heart, gastrointestinal system, kidneys, or genitalia; and distinctive facial features. 1p36 deletion syndrome is caused by a deletion of genetic material from a specific region in the short (p) arm of chromosome 1. Most cases are not inherited. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.