Conditions in the PIK3CA-related overgrowth spectrum (PROS), such as CLOVES syndrome, fibroadipose hyperplasia, and megalencephaly-capillary malformation (MCAP), are very rare diseases. Doctors usually diagnose them right after a child is born or a little later in childhood, when they notice that your child has symptoms that can come from a PIK3CA gene mutation.
Each child with a PROS disease may have very different symptoms based on which body parts are affected by the gene mutation. But some of the ones that doctors notice first include:
- Port-wine stains or large birthmarks on the skin
- Large, fatty growths on the torso or back
- Uneven arms or legs
- Enlarged veins
- Webbed fingers or toes
- Wide, triangle-shaped feet
- Larger head on one side
- Spine problems
- Bladder problems
- Extra fingers or toes
- Enlarged tongue
Based on these signs, doctors can perform tests to confirm the diagnosis and rule out other causes of your child’s symptoms.
Physical Exam
Diagnosis begins with a physical exam by a pediatrician. They’ll look closely at areas of their body that show signs of unusual overgrowth. They’ll also test how well parts of the body work. For example, a doctor may check your child’s heart, since children with CLOVES syndrome may have heart problems from blood vessels that are growing too large. MCAP may cause seizures, low muscle tone, or learning delays because it affects brain and head growth.
Imaging
Scans help your child’s doctor see signs of overgrown tissue inside their body. No single imaging test can diagnose a PROS disease. Your child may need more than one scan depending on their condition or the parts of their body that are affected.
Imaging tests may include:
- X-rays
- Ultrasound
- Magnetic resonance imaging (MRI)
- Computed tomography (CT) scan
In some cases, it’s possible to diagnose a PROS disease before birth with an ultrasound. Your prenatal scan may show unusual growths or fat deposits on your baby that could be caused by the PI3CKA mutation. But because PROS conditions are so rare, some doctors may not be aware of these signs or what they mean.
Lab Tests
Lab tests also help diagnose PROS diseases. Your pediatrician can remove a small piece of tissue from the part of your child’s body where they suspect cells are growing out of control. A lab tests the tissue for the PIK3CA gene mutation. For one type of PROS, MCAP, doctors can test a blood or saliva sample instead. But for most of the conditions, the mutation only shows up in tissue cells, not in blood cells.
Some genetic tests will be negative even if a child has a PROS disease. That’s because the gene mutation only affects cells in certain parts of the body. Your child may need to have more than one tissue sample tested.
Unlike other types of genetic problems, PIK3CA gene mutations don’t run in families, and parents don’t pass them to their children. So if you have a family member with PROS, that doesn’t mean your child has a higher chance of having it. It’s not a disease that you need to screen for before you try to have a baby.