Emanuel syndrome, also known as derivative 22 syndrome, or der syndrome, is a rare disorder associated with multiple congenital anomalies, including profound intellectual disability, preauricular skin tags or pits, and conotruncal heart defects. It can occur in offspring of carriers of the constitutional chromosomal translocation t, owing to a 3:1 meiotic malsegregation event resulting in partial trisomy of chromosomes 11and 22. An unbalanced translocation between chromosomes 11 and 22 is described as Emanuel syndrome. It was first described in 1980 by American medical researchers Beverly S. Emanuel and Elaine H. Zackai as well as a consortium of European scientists the same year.
Sign and symptoms
Infants with Emanuel syndrome have weak muscle tone and fail to gain weight and grow at the expected rate. Their development is significantly delayed, and most affected individuals have severe to profound intellectual disability. Other features of Emanuel syndrome include an unusually small head, distinctive facial features and a small lower jaw. Ear abnormalities are common, including small holes in the skin just in front of the ears. About half of all affected infants are born with an opening in the roof of the mouth or a high arched palate. Males with Emanuel syndrome often have genital abnormalities. Additional signs of this condition can include heart defects and absent or unusually small kidneys; these problems can be life-threatening in infancy or childhood.
People with Emanuel syndrome typically inherit the der chromosome from an unaffected parent. The parent carries a chromosomal rearrangement between chromosomes 11 and 22 called a balanced translocation. No genetic material is gained or lost in a balanced translocation, so these chromosomal changes usually do not cause any health problems. As this translocation is passed to the next generation, it can become unbalanced. Individuals with Emanuel syndrome inherit an unbalanced translocation between chromosomes 11 and 22 in the form of a der chromosome. These individuals have two normal copies of chromosome 11, two normal copies of chromosome 22 and extra genetic material from the der chromosome. As a result of the extra chromosome, people with Emanuel syndrome have three copies of some genes in each cell instead of the usual two copies. The excess genetic material disrupts the normal course of development, leading to intellectual disability and birth defects. Researchers are working to determine which genes are included on the der chromosome and what role these genes play in development.
Emanuel syndrome does not have a cure, but individual symptoms may be treated. Assessments of individual systems, such as the cardiovascular, gastrointestinal, orthopedic and neurological, may be necessary to determine the extent of impairment and options for treatment.
