Understanding PIK3CA-Related Overgrowth Spectrum (PROS): Symptoms, Causes, and Treatment

Key Takeaways

  • Somatic PIK3CA mutations occur during embryonic development, affecting only certain body tissues rather than being inherited from parents—this mosaic pattern explains why overgrowth is typically asymmetric and localized.
  • Common manifestations include hemimegalencephaly (enlarged brain hemisphere causing seizures in 80% of cases), macrodactyly (enlarged fingers/toes), and lipomatous overgrowth that can compress nerves and blood vessels.
  • Vascular malformations occur in approximately 60% of patients, ranging from capillary malformations (port-wine stains) to complex venous and lymphatic abnormalities that may cause bleeding or clotting complications.
  • Alpelisib, a PI3K inhibitor approved in 2022, can reduce overgrowth by 20-30% in clinical trials, though it requires careful monitoring for hyperglycemia and other metabolic side effects.
  • Surgical debulking is often necessary when overgrowth causes functional impairment, but tissue typically regrows within 2-5 years, requiring repeat procedures throughout childhood and adolescence.

PIK3CA-Related Overgrowth Spectrum (PROS) is a group of rare syndromes that cause certain parts of the body to grow too much or develop an unusual shape. These conditions are present at birth but may not be noticeable until later in life. In this article, we'll explore the causes, symptoms, and treatment options for PROS.

What Causes PROS?

PROS is caused by changes, or mutations, in a gene called PIK3CA. This gene provides instructions for making a protein that controls cell growth, division, movement, and death. When the PIK3CA gene is mutated, the protein doesn't function properly, leading to mistakes in cell growth. These mistakes can cause cells to grow and divide too quickly or live too long, resulting in overgrowth or unusual shapes in affected body parts.

Understanding PIK3CA-Related Overgrowth Spectrum (PROS): Symptoms, Causes, and Treatment

Types of PROS

There are several syndromes that fall under the PROS umbrella, including:

  • Fibroadipose hyperplasia: Causes patchy growths on limbs or other body parts due to overgrowth of fatty or fibrous tissue or blood vessels.

  • CLOVES syndrome: Characterized by congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal anomalies.

  • Megalencephaly-capillary malformation (MCAP) syndrome: Causes overgrowth of the brain and other body parts, such as blood vessels and parts of the face.

  • Hemihyperplasia-multiple lipomatosis (HHML) syndrome: Affects the growth of arms and legs, causing slow-growing and painless fatty masses under the skin.

  • Hemimegalencephaly: Involves enlargement of all or half of the brain, along with changes in blood vessels.

  • Facial infiltrating lipomatosis: Causes painless swelling or overgrowth of part of the face, often on one side of the head.

Symptoms of PROS

The symptoms of PROS can vary depending on the specific syndrome and the affected body parts. Some common symptoms include:

  • Overgrowth of specific body parts

  • Unusual shape or size of affected areas

  • Vascular malformations (birthmarks or prominent veins)

  • Fatty masses under the skin

  • Skeletal abnormalities (curved spine, large hands/feet)

  • Developmental delays or learning differences (when the brain is affected)

Treatment Options for PROS

While there is no cure for PROS, there are ways to manage the condition and its symptoms. Treatment options may include:

  • Surgery: To remove overgrowths, relieve pressure on the brain, correct scoliosis, or manage other problems.

  • Medications: To control seizures or other symptoms.

  • Monitoring: Regular check-ups to assess the condition and address any new concerns.

It's essential to work closely with a healthcare team experienced in treating PROS to develop an individualized treatment plan. For more information on PROS and its management, consult the following resources:

Remember, every person with PROS is unique, and the outlook and symptoms can vary significantly from one individual to another. Work with your healthcare team to understand your or your child's specific situation and to develop the most appropriate care plan.

The Bottom Line

This complex overgrowth disorder requires lifelong multidisciplinary management, with treatment tailored to each patient's specific pattern of affected tissues. Early diagnosis and intervention can prevent complications like seizures, nerve compression, and vascular emergencies. If you notice asymmetric growth patterns, unusual birthmarks, or related symptoms in yourself or your child, Doctronic can help connect you with appropriate specialist care.

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