Beckwith–Wiedemann syndrome

Beckwith-Wiedemann syndrome
Classification and external resources
Specialty medical genetics
ICD-10 Q87.3
ICD-9-CM 759.89
OMIM 130650
DiseasesDB 14141
MedlinePlus 001186
eMedicine ped/218
Patient UK Beckwith–Wiedemann syndrome
MeSH C16.131.077.133
GeneReviews

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. Beckwith syndrome can also cause child behavior problems.

Common features used to define BWS are:[1]

History

Originally, Dr. Hans-Rudolf Wiedemann (born 16 February 1915, Bremen, Germany,[2] 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). Over time, this constellation was renamed Beckwith–Wiedemann syndrome following the autoptical observations of Prof. John Bruce Beckwith (born 18 September 1933, Spokane, Washington),[3] who also observed a severe increase in the size of the adrenal glands in some of these patients.

Presentation

Most children with BWS do not have all of these five features. In addition, some children with BWS have other findings including: nevus flammeus, prominent occiput, midface hypoplasia, hemihypertrophy, genitourinary anomalies (enlarged kidneys), cardiac anomalies, musculoskeletal abnormalities, and hearing loss. Also, some premature newborns with BWS do not have macroglossia until closer to their anticipated delivery date.[4]

Given the variation among individuals with BWS and the lack of a simple diagnostic test, identifying BWS can be difficult. In an attempt to standardize the classification of BWS, DeBaun et al. have defined a child as having BWS if the child has been diagnosed by a physician as having BWS and if the child has at least two of the five common features associated with BWS (macroglossia, macrosomia, midline abdominal wall defects, ear creases/ear pits, neonatal hypoglycemia).[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 pits, nevus flammeus, neonatal hypoglycemia, nephromegaly, or hemihyperplasia).[6]

While most children with BWS do not develop cancer, children with BWS do have a significantly increased risk of cancer. Children with BWS are most at risk during early childhood and should receive cancer screening during this time.

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.

Occurrence

Beckwith–Wiedemann syndrome has an estimated incidence of one in 13,700; about 300 children with BWS are born each year in the United States.[7] The exact incidence of BWS is unknown because of the marked variability in the syndrome's presentation and difficulties with diagnosis. The number of reported infants born with BWS is most likely low because many are born with BWS, but have clinical features that are less prominent and therefore missed. BWS has been documented in a variety of ethnic groups and occurs equally in males and females.

Children conceived through In vitro fertilization have a three to fourfold increased chance of developing Beckwith–Wiedemann syndrome. It is thought that this is due to genes being turned on or off by the IVF procedures.[8][9]

Genetics

Most (>85%) cases of BWS are sporadic, meaning that usually no one else in that family has BWS and parents of an affected child are not at increased risk of having other children with BWS. However, some (<15%) cases of BWS are familial, meaning that someone else in that family may also have BWS and parents of an affected child may be at increased risk of having other children with BWS. BWS has been shown to specifically involve problems with a defined region on the short arm of chromosome 11 referred to as 11p15, that leads to overactivity of the IGF-2 gene (growth factor) and/or no active copy of CDKN1C (inhibitor of cell proliferation).

BWS can be caused by a range of different genetic defects. Over five distinct errors involving 11p15 have been identified in different BWS patients. Some patients have maternal chromosomal rearrangements of 11p15, meaning that there is a disruption of the chromosome in this region. Other patients have paternal uniparental disomy (UPD) of chromosome 11, meaning that the maternal copy of this chromosome is replaced with an extra paternal copy. Many other patients have abnormal DNA methylation in different areas of 11p15, meaning that normal epigenetic marks that regulate imprinted genes in this region are altered. A few other patients have a single gene located within 11p15.

Additionally, even after extensive molecular testing, the specific defect causing BWS in an affected individual may remain unknown. In about 1/3 of BWS patients, the genetic or epigenetic mutation is unknown. This fact demonstrates why BWS remains a clinical diagnosis because physicians cannot identify and test for all the genetic causes of BWS. 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. When molecular analyses were completed in children who met a research criterion for BWS, only 7 of 10 children had genetic or epigenetic mutations.[5] The absence of a mutation in a child with clinical findings suggestive of BWS should not preclude a diagnosis of BWS.

Given that the genetics of BWS are complex, a child with BWS should be under the medical care of a geneticist or an expert in the management of BWS.

Genes involved are IGF-2, CDKN1C, H19, and KCNQ1OT1.[10]

Association with CDKN1C

CDKN1C is a protein coding gene that encodes a cyclin-dependent kinase inhibitor that acts as a negative regulator of cell proliferation, effectively making CDKN1C a tumor suppressor gene. CDKN1C also works during fetal development, preventing the fetus from becoming too large. It is located on the short arm of the human chromosome 11 in the ICR2 region, along with many other imprinted genes. Since CDKN1C is preferentially maternally expressed, hypomethylation in the ICR2 region of the maternal allele can result in pathologies such as cancer or a defect known as Beckwith-Weidemann Syndrome. Beckwith-Weidemann Syndrome (BWS) may also be brought about by CDKN1C 11p15 epimutations. It may also be a result of deletions of small amounts of DNA that cause chromosomal abnormalities, rendering the gene inactive. This leaves only the paternally expressed IGF2 to promote cell proliferation. The reduction of growth restriction results in the overgrowth of many tissues, leading to the common symptoms of BWS. These symptoms may include macroglossia, organomegaly, periorbital fullness, and hernias. 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.[11]

Management

Abdominal wall defects are common in newborns with BWS and may require surgical treatment. These defects can range in severity from omphalocele (most serious) to umbilical hernia and diastasis recti (least serious). An omphalocele is a congenital malformation in which a newborn's intestines, and sometimes other abdominal organs, protrude out of the abdomen through the umbilicus. Newborns with an omphalocele typically require surgery to place the abdominal contents back into the abdomen in order to prevent serious infection or shock. An umbilical hernia is also a defect in which abdominal contents come through weak abdominal wall muscle at the umbilicus. In general, newborns with umbilical hernias do not require treatment because often these hernias spontaneously close by age four. If, after this time, a hernia is still present, surgery may be recommended. Diastasis recti is a separation of the left and right sides of the rectus abdominis muscle that are normally joined together. Children with diastasis recti usually require no treatment because the condition resolves as the child grows.

Neonatal hypoglycemia, low blood glucose in the first month of life, occurs in about half of children with BWS.[12] Most of these hypoglycemic newborns are asymptomatic and have a normal blood glucose level within days. However, untreated persistent hypoglycemia can lead to permanent brain damage. Hypoglycemia in newborns with BWS should be managed according to standard protocols for treating neonatal hypoglycemia. Usually this hypoglycemia can easily be treated with more frequent feedings or medical doses of glucose. Rarely (<5%) children with BWS will continue to have hypoglycemia after the neonatal period and require more intensive treatment.[5] Such children may require tube feedings, oral hyperglycemic medicines, or a partial pancreatectomy.

Macroglossia, a large tongue, is a very common (>90%) and prominent feature of BWS. Infants with BWS and macroglossia typically cannot fully close their mouth in front of their large tongue, causing it to protrude out. Macroglossia in BWS becomes less noticeable with age and often requires no treatment; but it does cause problems for some children with BWS. In severe cases, macroglossia can cause respiratory, feeding, and speech difficulties. Children with BWS and significant macroglossia should be evaluated by a craniofacial team.

The best time to perform surgery for a large tongue is not known. Some surgeons recommend performing the surgery between 3 and 6 months of age. 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.

Nevus flammeus (port-wine stain) is a flat, red birthmark caused by a capillary (small blood vessel) malformation. Children with BWS often have nevus flammeus on their forehead or the back of their neck. Nevus flammeus is benign and commonly does not require any treatment.

Hemihypertrophy (hemihyperplasia) is an abnormal asymmetry between the left and right sides of the body occurring when one part of the body grows faster than normal. Children with BWS and hemihypertrophy can have an isolated asymmetry of one body part, or they can have a difference affecting the entire one side of the body. Individuals who do not have BWS can also have hemihypertrophy. Isolated hemihypertrophy is associated with a higher risk for cancer.[13] The types of cancer and age of the cancers are similar to children with BWS. As a result, children with hemihypertrophy should follow the general cancer screening protocol for BWS.

Hemihypertrophy can also cause various orthopedic problems, so children with significant limb hemihyperplasia should be evaluated and followed by an orthopedic surgeon.

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

Neoplasms

Most children (>80%) with BWS do not develop cancer; however, children with BWS are much more likely (~600 times more) than other children to develop certain childhood cancers, particularly Wilms' tumor (nephroblastoma), pancreatoblastoma and hepatoblastoma.[1] Individuals with BWS appear to only be at increased risk for cancer during childhood (especially before age four) and do not have an increased risk of developing cancer in adulthood.[1] If 100 children with BWS were followed from birth until age ten, about 10 cases of cancer would be expected in the group before age four, and about 1 case of cancer in the group would be expected between age four and ten.

In addition to Wilms tumor and hepatoblastoma, children with BWS are also at increased risk of developing adrenal cortical carcinoma, neuroblastoma, and rhabdomyosarcoma.

Both Wilms tumor and hepatoblastoma can usually be cured if diagnosed early. Early diagnosis allows physicians to treat the cancer when it is at an early stage. In addition, there is less toxic treatment.[14] Given the importance of early diagnosis, all children with BWS should receive cancer screening.

An abdominal ultrasound every 3 months until at least eight years of age is recommended[14] and a blood test to measure alpha-fetoprotein (AFP) every 6 weeks until at least four years of age.[15] Families and physicians should determine screening schedules for specific patients, especially the age at which to discontinue screening, based upon their own evaluation of the risk-benefit ratio.

Prognosis

In general, the prognosis is very good. Children with BWS usually do very well and grow up to become the heights expected based on their parents' heights. While children with BWS are at increased risk of childhood cancer, most children with BWS do not develop cancer and the vast majority of children who do develop cancer can be treated successfully.

Children with BWS for the most part had no significant delays when compared to their siblings. However, some children with BWS do have speech problems that could be related to macroglossia or hearing loss.

Advances in treating neonatal complications and premature infants in the last twenty years have significantly improved the true infant mortality rate associated with BWS. In a review of pregnancies that resulted in 304 children with BWS, no neonatal deaths were reported.[16] This is compared to a previously reported mortality rate of 20%.[17] The data from the former study was derived from a BWS registry, a database that may be slightly biased towards involving living children; however, death was not an exclusion criterion to join the registry. This suggests that while infants with BWS are likely to have a higher than normal infant mortality risk, it may not be as high as 20%.

Assisted reproductive technology

Assisted reproductive technology (ART) is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. According to the CDC, in general, ART procedures involve surgically removing eggs from a woman's ovaries, combining them with sperm in the laboratory, and returning them to the woman's body or donating them to another woman. ART has been associated with epigenetic syndromes, specifically BWS and Angelman syndrome. Three groups have shown an increased rate of ART conception in children with BWS.[5][18][19][20] A retrospective case control study from Australia found a 1 in 4000 risk of BWS in their in-vitro population, several times higher than the general population.[21] Another study found that children conceived by in vitro fertilisation (IVF) are three to four times more likely to develop the condition.[22] No specific type of ART has been more closely associated with BWS.[20] The mechanism by which ART produces this effect is still under investigation.

History

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.[23][24] Originally termed EMG syndrome (for exomphalos, macroglossia, and gigantism), this syndrome over time became known as Beckwith–Wiedemann syndrome or Wiedemann Beckwith syndrome.

See also

References

  1. 1 2 3 DeBaun MR, Tucker MA (March 1998). "Risk of cancer during the first four years of life in children from The Beckwith-Wiedemann Syndrome Registry". The Journal of Pediatrics. 132 (3 Pt 1): 398–400. doi:10.1016/S0022-3476(98)70008-3. PMID 9544889.
  2. ↑ Biographical notes Wiedemann
  3. ↑ Biographical note
  4. ↑ Motokura T, Bloom T, Kim HG, et al. (April 1991). "A novel cyclin encoded by a bcl1-linked candidate oncogene". Nature. 350 (6318): 512–5. doi:10.1038/350512a0. PMID 1826542.
  5. 1 2 3 4 DeBaun MR, Niemitz EL, McNeil DE, Brandenburg SA, Lee MP, Feinberg AP (March 2002). "Epigenetic alterations of H19 and LIT1 distinguish patients with Beckwith-Wiedemann syndrome with cancer and birth defects". American Journal of Human Genetics. 70 (3): 604–11. doi:10.1086/338934. PMC 384940Freely accessible. PMID 11813134.
  6. ↑ Elliott M, Bayly R, Cole T, Temple IK, Maher ER (August 1994). "Clinical features and natural history of Beckwith-Wiedemann syndrome: presentation of 74 new cases". Clinical genetics. 46 (2): 168–74. doi:10.1111/j.1399-0004.1994.tb04219.x. PMID 7820926.
  7. ↑ Thorburn MJ, Wright ES, Miller CG, Smith-Read EH (April 1970). "Exomphalos-macroglossia-gigantism syndrome in Jamaican infants". American Journal of Diseases of Children. 119 (4): 316–21. doi:10.1001/archpedi.1970.02100050318006. PMID 5434588.
  8. ↑ BBC, Horizon (2005). "BBC - Science & Nature - Horizon". Archived from the original on 2005-12-04. Retrieved 2010-09-29. Beckwith-Wiedemann Syndrome – a rare disorder linked to abnormal gene expression. It has been shown that babies conceived by IVF have a three- to four-fold increased chance of developing this condition.
  9. ↑ "BBC_-_Horizon_-_2005_-_The_Ghost_In_Your_Genes.avi". BBC Horizon. BBC. 2005. Retrieved 2010-09-30. See from time offset 16:40 in the video
  10. ↑ Online Mendelian Inheritance in Man (OMIM) 130650
  11. ↑ Pappas, J. (April 2015). "The Clinical Course of an Overgrowth Syndrome, From Diagnosis in Infancy Through Adulthood: The Case of Beckwith-Weidemann Syndrome". Current Problems in Pediatric and Adolescent Healthcare. 45 (4): 112–117.
  12. ↑ DeBaun MR, King AA, White N (April 2000). "Hypoglycemia in Beckwith-Wiedemann syndrome". Seminars in perinatology. 24 (2): 164–71. doi:10.1053/sp.2000.6366. PMID 10805171.
  13. ↑ Hoyme HE, Seaver LH, Jones KL, Procopio F, Crooks W, Feingold M (October 1998). "Isolated hemihyperplasia (hemihypertrophy): report of a prospective multicenter study of the incidence of neoplasia and review". American Journal of Medical Genetics. 79 (4): 274–8. doi:10.1002/(SICI)1096-8628(19981002)79:4<274::AID-AJMG8>3.0.CO;2-M. PMID 9781907.
  14. 1 2 Choyke PL, Siegel MJ, Craft AW, Green DM, DeBaun MR (March 1999). "Screening for Wilms tumor in children with Beckwith-Wiedemann syndrome or idiopathic hemihypertrophy". Medical and pediatric oncology. 32 (3): 196–200. doi:10.1002/(SICI)1096-911X(199903)32:3<196::AID-MPO6>3.0.CO;2-9. PMID 10064187.
  15. ↑ Clericuzio CL, Chen E, McNeil DE, et al. (August 2003). "Serum alpha-fetoprotein screening for hepatoblastoma in children with Beckwith-Wiedemann syndrome or isolated hemihyperplasia". The Journal of Pediatrics. 143 (2): 270–2. doi:10.1067/S0022-3476(03)00306-8. PMID 12970646.
  16. ↑ Wangler MF, Chang AS, Moley KH, Feinberg AP, Debaun MR (April 2005). "Factors associated with preterm delivery in mothers of children with Beckwith-Wiedemann syndrome: a case cohort study from the BWS registry". American Journal of Medical Genetics Part A. 134A (2): 187–91. doi:10.1002/ajmg.a.30595. PMID 15723285.
  17. ↑ Pettenati MJ, Haines JL, Higgins RR, Wappner RS, Palmer CG, Weaver DD (October 1986). "Wiedemann-Beckwith syndrome: presentation of clinical and cytogenetic data on 22 new cases and review of the literature". Human Genetics. 74 (2): 143–54. doi:10.1007/BF00282078. PMID 3770742.
  18. ↑ Gicquel C, Gaston V, Mandelbaum J, Siffroi JP, Flahault A, Le Bouc Y (May 2003). "In vitro fertilization may increase the risk of Beckwith-Wiedemann syndrome related to the abnormal imprinting of the KCN1OT gene". American Journal of Human Genetics. 72 (5): 1338–41. doi:10.1086/374824. PMC 1180288Freely accessible. PMID 12772698.
  19. ↑ Maher ER, Brueton LA, Bowdin SC, et al. (January 2003). "Beckwith-Wiedemann syndrome and assisted reproduction technology (ART)". Journal of Medical Genetics. 40 (1): 62–4. doi:10.1136/jmg.40.1.62. PMC 1735252Freely accessible. PMID 12525545.
  20. 1 2 Chang AS, Moley KH, Wangler M, Feinberg AP, Debaun MR (February 2005). "Association between Beckwith-Wiedemann syndrome and assisted reproductive technology: a case series of 19 patients". Fertility and Sterility. 83 (2): 349–54. doi:10.1016/j.fertnstert.2004.07.964. PMID 15705373.
  21. ↑ Halliday J, Oke K, Breheny S, Algar E, J Amor D (September 2004). "Beckwith-Wiedemann syndrome and IVF: a case-control study". American Journal of Human Genetics. 75 (3): 526–8. doi:10.1086/423902. PMC 1182036Freely accessible. PMID 15284956.
  22. ↑ Gosden R, Trasler J, Lucifero D, Faddy M (2003). "Rare congenital disorders, imprinted genes, and assisted reproductive technology". Lancet. 361 (9373): 1975–7. doi:10.1016/S0140-6736(03)13592-1. PMID 12801753.
  23. ↑ Beckwith, J. Bruce (1963). "Extreme cytomegaly of the adrenal fetal cortex, omphalocele, hyperplasia of kidneys and pancreas, and Leydig cell hyperplasia - another syndrome?". Annual Meeting of the Western Society for Pediatric Research. Los Angeles.
  24. ↑ Wiedemann HR (September 1964). "Familial malformation complex with umbilical hernia and macroglossia - a "new syndrome"?". Journal de génétique humaine (in French). 13: 223–32. PMID 14231762.

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