Beckwith–Wiedemann syndrome (/ˈbɛkˌwɪθ ˈviːdə.mən/; abbreviated BWS) is an overgrowth disorder usually present at birth, characterized by an increased risk of childhood cancer and certain congenital features.

[5] Another definition presented by Elliot et al. includes the presence of either three major features (anterior abdominal wall defect, macroglossia, or prepostnatal overgrowth) or two major plus three minor findings (ear creases, nevus flammeus, neonatal hypoglycemia, nephromegaly, or hemihyperplasia).

[6] In general, children with BWS do very well and grow up to become adults of normal size and intelligence, usually without the syndromic features of their childhood.

In addition to Wilms tumor and hepatoblastoma, children with BWS have been shown in individual case reports to develop ganglioneuroma, adrenocortical carcinoma, acute lymphoid leukemia, liver sarcoma, thyroid carcinoma, melanoma, rhabdomyosarcoma, and mesoblastic nephroma.

Many other patients have abnormal DNA methylation in different areas of 11p15.5, meaning that normal epigenetic marks that regulate imprinted genes in this region are altered.

Even after extensive molecular testing, the specific defect causing BWS in an affected individual may remain unknown.

The clinical definition used for BWS is limited, because no standard diagnostic criteria exist that have been independently verified with patients who have either genetic or epigenetic mutations.

It may also be a result of deletions of small amounts of DNA that cause chromosomal abnormalities, rendering the gene inactive.

Knockout models for CDKN1C in mice do exist; in fact, many of the affected offspring exhibit fetal and neonatal lethality and have most of the features related to Beckwith-Weidemann Syndrome.

Newborns with an omphalocele typically require surgery to place the abdominal contents back into the abdomen in order to prevent serious infection or shock.

[citation needed] Neonatal hypoglycemia, low blood glucose in the first month of life, occurs in about half of children with BWS.

Rarely (<5%) children with BWS will continue to have hypoglycemia after the neonatal period and require more intensive treatment.

Infants with BWS and macroglossia typically cannot fully close their mouth in front of their large tongue, causing it to protrude out.

Surgery for macroglossia involves removing a small part of the tongue so that it fits within the mouth to allow for proper jaw and tooth development.

These teams include speech and language therapists, craniofacial and paediatric plastic surgeons, and orthodontists who decide the appropriateness and timing of tongue reduction surgery.

For example, in the United Kingdom, children who have macroglossia associated with Beckwith Wiedemann Syndrome are managed in a national specialised service.

[15] Nevus flammeus (port-wine stain) is a flat, red birthmark caused by a capillary (small blood vessel) malformation.

Hemihyperplasia affecting the face can sometimes cause significant cosmetic concerns that may be addressed by a cranial facial team.

While they are at increased risk of childhood cancer, most of them do not develop the disease, and the vast majority of the children who do can be treated successfully.

[24] The exact incidence of BWS is unknown because of the marked variability in the syndrome's presentation and difficulties with diagnosis.

[citation needed] Children conceived through in vitro fertilization have a three to fourfold increased chance of developing Beckwith–Wiedemann syndrome.

[25][26][27] In the 1960s, Dr. John Bruce Beckwith, an American pathologist and Dr. Hans-Rudolf Wiedemann, a German pediatrician, independently reported cases of a proposed new syndrome.

[citation needed] Originally, Dr. Hans-Rudolf Wiedemann (born 16 February 1915, Bremen, Germany, died 4 August 2006, Kiel) coined the term exomphalos-macroglossia-gigantism (EMG) syndrome to describe the combination of congenital abdominal wall defects as hernia (exomphalos), large tongues (macroglossia), and large bodies and/or long limbs (gigantism).