WAGR syndrome is a disorder that affects many body systems and is named for its main features: Wilms tumor, anirida, genitourinary anomalies, and intellectual disability (formerly referred to as mental retardation).
People with WAGR syndrome have a 45 to 60 percent chance of developing Wilms tumor, a rare form of kidney cancer. This type of cancer is most often diagnosed in children but is sometimes seen in adults.
Most people with WAGR syndrome have aniridia, an absence of the colored part of the eye (the iris). This can cause reduction in the sharpness of vision (visual acuity) and increased sensitivity to light (photophobia). Aniridia is typically the first noticeable sign of WAGR syndrome. Other eye problems may also develop, such as clouding of the lens of the eyes (cataracts), increased pressure in the eyes (glaucoma), and involuntary eye movements (nystagmus).
Abnormalities of the genitalia and urinary tract (genitourinary anomalies) are seen more frequently in males with WAGR syndrome than in affected females. The most common genitourinary anomaly in affected males is undescended testes (cryptorchidism). Females may not have functional ovaries and instead have undeveloped clumps of tissue called streak gonads. Females may also have a heart-shaped (bicornate) uterus, which makes it difficult to carry a pregnancy to term.
Another common feature of WAGR syndrome is intellectual disability. Affected individuals often have difficulty processing, learning, and properly responding to information. Some individuals with WAGR syndrome also have psychiatric or behavioral problems including depression, anxiety, attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), or a developmental disorder called autism that affects communication and social interaction.
Other signs and symptoms of WAGR syndrome can include childhood-onset obesity, inflammation of the pancreas (pancreatitis), and kidney failure. When WAGR syndrome includes childhood-onset obesity, it is often referred to as WAGRO syndrome.
The prevalence of WAGR syndrome ranges from 1 in 500,000 to one million individuals. It is estimated that one-third of people with aniridia actually have WAGR syndrome. Approximately 7 in 1,000 cases of Wilms tumor can be attributed to WAGR syndrome.
The signs and symptoms of WAGR syndrome are related to the loss of multiple genes on the short arm of chromosome 11. WAGR syndrome is often described as a contiguous gene deletion syndrome because it results from the loss of several neighboring genes. The PAX6 and WT1 genes are always deleted in people with the typical signs and symptoms of this disorder. Because changes in the PAX6 gene can affect eye development, researchers think that the loss of the PAX6 gene is responsible for the characteristic eye features of WAGR syndrome. The PAX6 gene may also affect brain development. Wilms tumor and genitourinary abnormalities are often the result of mutations in the WT1 gene, so deletion of the WT1 gene is very likely the cause of these features in WAGR syndrome.
In people with WAGRO syndrome, the chromosome 11 deletion includes an additional gene, BDNF. This gene is active (expressed) in the brain and plays a role in the survival of nerve cells (neurons). The protein produced from the BDNF gene is thought to be involved in the management of eating, drinking, and body weight. Loss of the BDNF gene is likely responsible for childhood-onset obesity in people with WAGRO syndrome. People with WAGRO syndrome may be at greater risk of neurological problems such as intellectual disability and autism than those with WAGR syndrome. It is unclear whether this increased risk is due to the loss of the BDNF gene or other nearby genes.
Research is ongoing to identify additional genes deleted in people with WAGR syndrome and to determine how their loss leads to the other features of the disorder.
Most cases of WAGR syndrome are not inherited. They result from a chromosomal deletion that occurs as a random event during the formation of reproductive cells (eggs or sperm) or in earl