BWS Syndrome

Beckwith-Wiedemann Syndrome

Background
Beckwith-Wiedemann Syndrome is named after American pediatric pathologist Bruce Beckwith and German geneticist Hans Rudolph Wiedemann. It is classified as an overgrowth syndrome, which means affected infants are considerably larger than normal (macrosomia) and continue to grow and gain weight at an unusual rate during childhood.

In some children with BWS one side of the body grows larger than the other, this is known as hemi-hypertrophy.

The signs and symptoms of BWS vary amongst infants. A prominent distinguishing feature is nevus flammeus, a strawberry mark found on the forehead and eyelids, sometimes known as ‘Stork bites’.

Many affected children are born with a defect in the abdominal wall (omphalocoele) that allows internal organs to protrude through the umbilicus (belly button); lesser severity of this condition may be an umbilical hernia. Other major features include abnormally large abdominal organs (visceromegaly); creases or depressions near the ears or low set ears; low blood sugar (hypoglycemia) in infancy and kidney abnormalities.

Children with BWS (about 10%) are at an increased risk of developing several types of benign or malignant tumors. In particular a rare form of kidney cancer called Wilm’s tumor (most common type in BWS, affecting 5-7% by age 7 or 8), cancer of soft tissue (rhabdomyosarcoma), and a form of liver cancer (hepatoblastoma). These children need close surveillance because most tumors occur in childhood (highest risk in first 4 years, lower between 5 and 10, and near the risk of baseline cancer in general population by age 10).

Occurrence – Worldwide occurrence is about 1 in 12,000. The condition however, is thought to be more common because many with mild symptoms are never diagnosed.

Genetics – abnormal gene regulation in a particular region of chromosome 11. Abnormal methylation of DNA disrupts normal regulatory process resulting in above phenotypic (physical) expressions.

It is an autosomal dominant pattern of inheritance which means that one copy of an altered gene in each cell is typically enough to express the disease. 85 percent of families have at least one affected family member, 10-15% have at least 2 or more. Parents of one child with BWS may be at a higher risk of having another child with the syndrome and that would depend on the genetic cause of the condition.

Of particular interest to plastic surgeons specialized in craniofacial disorders is an abnormally large tongue (macroglossia) which may cause significant functional problems i.e. interfere with breathing, feeding difficulties, excessive drooling and dentoskeletal deformity with growth.
Unfortunately, these symptoms may give a false impression of developmental delay or even mental retardation. Hence, it becomes a huge psychosocial concern.

Surgical Indication (Tongue Reduction):
The enlarged tongue may cause dentoskeletal deformity due to constant forward thrust to the lower jaw. Anterior cross bite (the lower teeth are on front of the upper teeth) or protruding tongue may result in an anterior open bite (Cannot close teeth together).

Surgery should be undertaken at a stage where teeth relationships are almost edge-to-edge. Clinical experience has shown that tongue reduction performed early may reverse this relationship (resulting in normal jaw relationship; upper teeth in front). In some instances even early cross bites have been corrected. Other indications include airway compromise and excessive drooling requiring multiple clothing changes per day.

Psychosocial concerns – most children with moderate size tongue may become orally continent (being able to keep tongue inside the mouth) by 6 years of age. However, this is a result of a conscious effort. The moment they focus on a particular task, the tongue may hang out of the mouth. This may lead to embarrassment or worse, teasing by peers.

Surgical procedure:
Dr. Sabry performs tongue reduction in children afflicted with BWS using the W-plasty method, which is the approach used by Dr. Jeffrey Marsh. (He was trained by Dr. Marsh at St. Louis Children’s Hospital).

W-plasty surgery is performed on the anterior (front) half to third of the tongue, leaving most of the important nerves and blood vessels untouched. The neurovascular bundle enters the posterior (back) aspect and travels through the middle. This maneuver significantly decreases the chance of excessive blood loss and changes in the motor function of the tongue.

The excision is performed in a W-fashion (W-plasty) and brought together with absorbable sutures in a conical shape. Once healed, the tip rounds out and gives the appearance of a near-normal tongue.

Complications:
The more dreaded complications such as airway compromise secondary to postop swelling or bleeding, requiring transfusion are more commonly seen with keyhole or L-reduction. Dr. Sabry uses the W-plasty method in which only the anterior and lateral parts of the tongue are addressed. Neither of the aforementioned complications are of major concern with this approach. Local wound healing may be seen at times but can be managed conservatively.

Postop Care:
Postoperatively, children are observed in the Intensive Care Unit for any breathing difficulty due to tongue swelling or for bleeding. They are maintained on IV hydration as most will be unwilling to eat or drink anything, sometimes for several days (4-6 days). Pain is controlled with intra-venous analgesics. No particular oral care is prescribed so as not to disturb the resorbable sutures.

Once the child starts to drink adequate fluids and is comfortable with oral analgesics, he/ she may be discharged home with parents.

Parents traveling a long distance for surgery are advised to remain in the area for approximately two weeks following discharge so as to ensure clinical stability and ready access to care should there be an emergency.

Long-term outcome:
Most children after tongue reduction are orally continent. Drooling improves significantly. Of particular interest is taste and speech. Even though sense of taste is difficult to gauge, we have observed changes in eating habits in youngsters post operatively. Children who previously avoided textured food were seed to be comfortable eating such after healing had ensued.

There is no report of any adverse effect of tongue reduction on speech at present.

Other syndromes resulting in macroglossia may include, Down’s syndrome, Simpson-Golabi-Behmel Syndrome, and Zimmerman-Laband Syndrome. Secondary causes may include mucopolysaccharide disorders, neurofibromas, lymphatic malformations, AVM or venous malformations.