PIK3CA-related overgrowth spectrum (PROS) refers to a group of rare disorders caused by mutations in the PIK3CA gene that result in cellular overgrowth of parts of the body.
PIK3CA is a commonly mutated gene found in solid cancers, but PIK3CA-related overgrowth spectrum disorders are benign (noncancerous) conditions. However, PROS causes some cells in the body to grow and divide more quickly, so people who have PROS can have an increased risk of cancer.
PIK3CA-related overgrowth spectrum disorders include:
- Fibroadipose hyperplasia (also called fibroadipose overgrowth)
- CLOVES syndrome
- Megalencephaly-capillary malformation syndrome (MCAP syndrome)
- Hemihyperplasia-multiple lipomatosis syndrome (HHML syndrome)
- Facial infiltrating lipomatosis (a congenital disorder that causes overgrowth of one side of the face)
What Are Symptoms of PIK3CA-Related Overgrowth Spectrum?
Symptoms of PIK3CA-related overgrowth spectrum (PROS) vary depending on disorder.
Symptoms of fibroadipose hyperplasia are usually not present at birth, typically worsen over time, and include:
- A patchy overgrowth of a limb or part of the body
- Problems walking due to the legs being a different length
- Problems moving a limb due to the overgrowth
- Challenges in regular daily activities due to deformity of a body part
Symptoms of CLOVES syndrome include:
- Fatty (lipomatous) growths that typically affect the trunk
- Blood vessel differences (vascular malformations)
- Patches or growths on the skin (epidermal nevi)
- Differences in the bones
- Curve in the spine (scoliosis)
- Very large fingers or toes (macrodactyly)
Symptoms of Megalencephaly-capillary malformation syndrome (MCAP syndrome) include:
- A very large brain (megalencephaly) or having one half of the brain larger than expected (hemimegalencephaly) which can cause:
- Low muscle tone (hypotonia)
- Intellectual disability
- Differences in the smallest blood vessels (capillaries)
- Fingers or toes that are fused together (syndactyly)
- Extra fingers or toes (polydactyly)
- Being very flexible (joint hypermobility)
- Heart abnormalities
Symptoms of Hemihyperplasia-multiple lipomatosis syndrome (HHML syndrome) include:
- Non-progressive, asymmetrical, moderate overgrowth usually affecting the limbs
- Slow-growing, painless, fatty masses under the skin distributed throughout the body
- Vascular malformations
Symptoms of Facial infiltrating lipomatosis (FIL) include:
- Overgrowth and enlargement of one side of the face
- Masses that grow from a nerve (mucosal neuromas)
- Enlargement of half of the tongue (hemi macroglossia)
- Bone enlargement
- Premature dental eruption
What Causes PIK3CA-Related Overgrowth Spectrum?
PIK3CA-related overgrowth spectrum (PROS) is caused by mutations in the PIK3CA gene.
- The PIK3CA gene provides instructions to the body to make a protein that helps control the signaling of other proteins. This protein helps many processes occur at the correct times including cell growth and division, cell movement, and cell survival.
- Changes in the PIK3CA gene result in the body not receiving instructions to make a certain signaling protein correctly. This causes errors in cell growth and division and how long a cell survives. When cells divide too fast or they live longer than they should, overgrowth of that part of the body can occur.
- PROS are not inherited disorders, that is, they are not passed from a parent to a child.
How Is PIK3CA-Related Overgrowth Spectrum Diagnosed?
PIK3CA-related overgrowth spectrum (PROS) is often diagnosed based on observation of characteristic signs and symptoms of the syndromes.
- A diagnosis of PROS is confirmed with genetic testing of the PIK3CA gene. Multiple samples of different tissues may need to be tested for the PIK3CA genetic change because genetic changes only occur in some cells of the body.
What Is the Treatment for PIK3CA-Related Overgrowth Spectrum?
There is no cure for PIK3CA-related overgrowth spectrum (PROS) and treatments are aimed at managing symptoms of the syndromes.
Treatments may include:
What Are Complications of PIK3CA-Related Overgrowth Spectrum?
Complications of PIK3CA-related overgrowth syndrome (PROS) may include:
- Severe overgrowth that may require surgery to help remove extra tissue, especially when causes problems in day-to-day life
- If overgrowth affects the brain and creates too much pressure, it may cause:
- Intellectual disability
- Developmental delay
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