Diagnosis and Testing
Why might a child be tested for Beckwith-Wiedemann syndrome?
Beckwith-Wiedemann syndrome may be suspected in children who were born larger than normal (macrosomia), with a birth defect where there is an outpouching of abdominal contents into the belly button (umbilical hernia or omphalocele) or who have a large tongue (macroglossia). As the child ages and certain parts of their body grow faster than others (hemihyperplasia), Beckwith-Wiedemann syndrome may be suspected. The condition also might be suspected in a child who has a close relative with Beckwith-Wiedemann syndrome, especially if the child has any of the common features of this condition.
More Diagnosis and Testing Content
How are children tested for Beckwith-Wiedemann syndrome?
Children who have symptoms suspicious for Beckwith-Wiedemann syndrome will generally have a karyotype performed. A karyotype is a photographic view of the chromosomes within a cell to look for missing or extra copies of one ore more chromosomes, missing or extra pieces of any of the chromosomes, and any abnormal layout or structure of one or more chromosomes. Often at the same time, methylation studies of the imprinting regions on chromosome 11 will be looked at. In cases in which other family members also have the condition, the CDKN1C gene may be looked at specifically to look for changes. In families in which there are multiple people with Beckwith-Wiedemann syndrome but a change in the CDKN1C gene was not found and the karyotype was normal, testing may be done to look for small areas of DNA that were duplicated or deleted. These tests are all typically done on a sample of blood taken from the arm.
Is there newborn testing for Beckwith-Wiedemann syndrome?
As of June 2019, Beckwith-Wiedemann syndrome is not on the Recommended Uniform Screen Panel (RUSP). The RUSP is created by the Health Resources and Services Administration, and states use this list to guide what conditions they screen for on newborn screening.
Is there more than one genetic test to diagnose Beckwith-Wiedemann syndrome?
Because there are several different genetic causes of Beckwith-Wiedemann syndrome, there are several different genetic tests that may be performed to diagnose the condition. The most common genetic tests include:
- Looking at the number and structure of the chromosomes through a test known as a karyotype
- Looking at the methylation patterns
- Looking for changes in the CDKN1C gene on the chromosome 11 received from the mother
- Looking to see if there are two paternally inherited copies of chromosome 11 being expressed at a specific location of chromosome 11p15.5
- Looking to see if there are duplications or segments of the DNA sequence that were flipped (inversions) or switched (translocations) at the region of interest on chromosome 11
Who else in my family should I test for Beckwith-Wiedemann syndrome?
Most people with Beckwith-Wiedemann syndrome are the only person in their family to have the condition. If certain genetic changes have been identified in an affected individual, then the parents of the person should also be tested even if they do not appear to have the condition. In order to determine if other family members, including parents of an affected individual, should be tested for Beckwith-Wiedemann syndrome, it would be helpful to meet with a medical geneticist or a genetic counselor to discuss these matters further. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website . Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Can Beckwith-Wiedemann syndrome be suspected prenatally?
Some, but not all, cases of Beckwith-Wiedemann syndrome can be suspected prenatally. If there is a known family history of Beckwith-Wiedemann syndrome and the pregnancy is at risk based on that history, the diagnosis may be suspected. About half of pregnancies involving a baby with Beckwith-Wiedemann syndrome may have too much amniotic fluid (polyhydramnios) and/or may have the entire body or parts of the body being larger than expected (macrosomia). A birth defect known as an omphalocele, where some of the abdominal organs spill into the belly button region, is often diagnosed prenatally. Although omphalocele can be seen in babies with chromosome disorders and genetic disorders other than Beckwith-Wiedemann syndrome, as well as as an isolated defect in a baby without an underlying genetic syndrome, Beckwith-Wiedemann syndrome should be considered as part of the differential diagnosis of a baby with an omphalocele. Other signs of the condition prenatally may include a long umbilical cord and a placenta that is almost twice as large as would be expected.