SNP Shot: Genomic Insights

Beckwith-Wiedemann syndrome (BWS) is a disorder impacting multiple body systems. It's considered an overgrowth syndrome, meaning newborns with BWS tend to be larger than average (macrosomia). Some children with BWS may also be taller than their peers, but this growth typically slows around age 8, and adults with the condition generally have normal height. Some children experience uneven growth of specific body parts on one side (hemihyperplasia), resulting in an asymmetrical appearance, but this asymmetry usually becomes less noticeable over time.

The symptoms and severity of BWS vary greatly among individuals. Some infants are born with an omphalocele, where abdominal organs protrude through an opening in the abdomen near the belly button. Umbilical hernias, soft bulges around the belly button, are also common. Macroglossia, an abnormally large tongue, can occur and may cause difficulties with breathing, swallowing, and speaking. Other common characteristics include enlarged abdominal organs (visceromegaly), creases or pits near the ears, low blood sugar (hypoglycemia) in infancy, and kidney problems.

Children with BWS have a higher risk of developing certain cancerous and noncancerous tumors, particularly Wilms tumor (a kidney cancer) and hepatoblastoma (a liver cancer). Approximately 10% of individuals with BWS develop tumors, almost always during childhood.

Most children and adults with BWS do not experience serious health complications and typically have a normal life expectancy.

Inheritance:

In approximately 85% of BWS cases, only one person in a family is diagnosed with the condition. However, parents of a child with BWS may have an increased risk of having other children with the same disorder, depending on the specific genetic cause. In 10-15% of cases, BWS affects multiple family members, often following an autosomal dominant inheritance pattern. This means that inheriting just one copy of an altered gene is usually enough to cause the disorder. However, a person with the altered gene may not show any symptoms, depending on which parent they inherited it from. In most cases linked to CDKN1C gene variations, individuals with BWS inherit the genetic change from their mothers. In rare instances, BWS is caused by changes in the structure of chromosome 11. Some of these chromosomal changes are inherited, while others occur randomly during the formation of egg or sperm cells, or in the early stages of development before birth.