Vision loss and obesity in children: Is there a genetic link?
Fact-checked by There are many possible causes of weight gain or eye problems in children, but when vision loss and obesity occur together, it could be a sign of the rare genetic condition Bardet-Biedl syndrome (BBS).
The genetic defects that cause BBS disrupt many tissues, including the eyes and the brain centers that regulate hunger. This is why BBS can be a challenge to diagnose — doctors must recognize distinct, seemingly unrelated symptoms, such as vision loss and weight gain, as manifestations of a single multisystemic disease.
Recognizing the signs of a genetic syndrome like BBS early enables the best possible care and long-term outcomes.
Why vision loss and obesity can be connected
There can be a genetic link between vision loss and obesity. Both the light-sensing cells in the eyes and the cells in the brain’s hunger control center, the hypothalamus, rely on cellular structures called cilia.
BBS belongs to a group of genetic disorders called ciliopathies, in which mutations cause defects in the structure or function of cilia, thereby affecting tissues that depend on cilia. Eye cells can progressively degenerate, leading to vision problems, and dysregulated hypothalamic signaling can lead to excessive hunger, overeating, and obesity.
Although they may initially seem unrelated, vision loss and obesity in children could be a sign of BBS or another ciliopathy.
How Bardet-Biedl syndrome affects the eyes
In BBS, cilia defects lead to rod-cone dystrophy, in which the light-sensing cells at the back of the eye (retina) progressively degenerate.
BBS vision loss from this process usually starts in childhood, beginning with difficulty seeing in low light or at night (night blindness) and blurriness at the edges of the visual field (tunnel vision). It then progresses to problems with daytime vision, often reaching legal blindness by adolescence or early adulthood.
Early signs parents may notice
BBS is rare, and its symptoms develop gradually. This can make it hard to identify the signs.
Early signs of vision changes in children with BBS could include:
- fear or hesitancy in darkness
- light sensitivity, or difficulty adjusting to light transitions
- clumsiness or falls, especially in low light
- squinting
- startling easily when someone approaches from the side
If night blindness in children or other vision issues arise alongside rapid weight gain and an intense drive to eat, it may be a sign that they should be tested for BBS.
When to ask about a genetic cause
If a child is exhibiting early-onset obesity and progressive vision issues, parents should speak with their doctors about whether genetic testing is warranted, especially if other signs of BBS, such as kidney or genital issues and developmental delays, are also present or emerging.
What testing may be recommended
If a physician suspects BBS based on the presence of symptoms, they’ll likely recommend a few different tests:
- Genetic testing: A blood sample or cheek swab will be tested for disease-causing mutations. These tests may look at genes specific to BBS or, depending on the symptoms, larger gene panels that include other ciliopathies, inherited retinal disease, and rare obesity.
- Comprehensive eye exam: An eye doctor will perform a series of specialized tests to evaluate the retina and look for changes consistent with BBS.
- Systemic screening: BBS affects many tissues, so doctors may order blood and imaging tests to evaluate the kidneys, reproductive system, and other organs.
How early diagnosis can help families plan
There is no cure for BBS, but an early and accurate diagnosis allows families and their doctors to develop a proactive care plan that improves quality of life and prevents complications. Because BBS is a disease that evolves, it will also help families know what to expect as their child gets older.
BBS is an inherited disease. When one family member is diagnosed, a genetic counselor can provide guidance on who else should be tested and what their results mean for family planning decisions.
Rare Obesity News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
