Read more about

Klippel-Trenaunay syndrome

Also known as
Klippel-Trenaunay syndrome
is a

Klippel-Trenaunay syndrome (KTS) is a rare disorder that is present at birth, and is characterized by three common features: port-wine stain (a birthmark also known as a capillary malformation), vascular malformation (abnormal veins) and limb overgrowth. Some patients may also have lymphatic malformation. These symptoms typically occur in the lower limbs, less commonly in the upper extremities and trunk. KTS belongs to a spectrum of overgrowth conditions known as PROS, which are caused by pathogenic variants in the PIK3CA gene.

Limb overgrowth in KTS is due to the overgrowth of soft tissue and bone, and can lead to a discrepancy in limb length, which may require corrective surgery. People with KTS are at increased risk for cellulitis, clotting problems, and gastrointestinal bleeding, most commonly from the rectum or bladder. Treatments are geared toward symptom reduction, pain management and minimizing potential complications such as infections.

Some common questions about KTS

What are the symptoms of KTS?

  • Port-wine stain (birthmark that grows with the child)
  • Limb overgrowth
  • Fused fingers/toes and/or extra fingers/toes
  • Lymphatic swelling 
  • Periodic infections due to poor lymphatic drainage 
  • Bleeding from the rectum, vagina or urinary bladder

What causes KTS?

Like other PROS conditions, KTS is caused by mosaic variations in the PIK3CA gene resulting in anomalies in the soft tissue, blood vessels, bone and internal organs. “Mosaic variations” means that the genetic variants that cause CLOVES are found in some cells of the body, but not in others. KTS is a sporadic condition and is not inherited from the parents. 

How many people get KTS?

According to Medline Plus, KTS is estimated to affect at least 1 in 100,000 people worldwide.

Read more about KTS

Stories from the KTS community

Hashtags to follow include #KlippelTrenaunaySyndrome and #KlippelTrenaunay

Are you a member of the KTS community with a resource to add to our list? Email us at!

KTS patient advocacy groups

  • Klippel-Trenaunay Support Group
    The K-T Support Group (Klippel-Trenaunay Support) was founded in 1986 to provide affected families with resources, education and a means to connect with one another.

Ways to get involved 

  • is an online resource from the National Institutes of Health (NIH) that provides access to information about clinical studies on a wide range of conditions.
  • Orphanet
    Orphanet is an online portal that provides access to information related to rare diseases for both patients and medical professionals in order to improve the diagnostic processes and treatments.
  • Rare as One Network
    The Rare as One Network, part of the Chan Zuckerberg Initiative, allows patients and family to share their thoughts in (paid) user studies in order to support the rare disease community.
  • AllStripes
    AllStripes is a Public Benefit Corporation on a mission to unlock new treatments for people affected by rare disease. Learn more about us by visiting our FAQs page.

KTS in the media

  • Report: Casey Martin has right leg amputated (10/16/2021)
    Former golf pro Casey Martin, who won the right to use a golf cart on the PGA tour in 2001 due to his KTS diagnosis, had his right leg amputated as a result of the condition. 

KTS resources

  • Understanding PROS
    A specialized website featuring detailed information on PROS conditions, as well as educational, downloadable resources on PROS conditions for both families and medical professionals. 
  • Health Insurance Marketplace
    If you do not currently have health insurance and live in the U.S., this link will help you determine if you are eligible for Medicaid or CHIP (Children’s Health Insurance Program). 

Other PROS conditions

Specific PROS conditions include, but are not limited to, the following: CLAPO syndrome, CLOVES syndrome, facial infiltrating lipomatosis (FIL), dysplastic megalencephaly (DMEG), fibroadipose hyperplasia or overgrowth (FAO/FH), fibro-adipose vascular anomaly (FAVA), focal cortical dysplasia (FCD), hemihyperplasia-multiple lipomatosis syndrome (HHML syndrome), hemimegalencephaly (HME), isolated lymphatic malformations (ILM), Klippel-Trenaunay syndrome (KTS), macrodactyly and megalencephaly-capillary malformation syndrome (M-CM/MCAP).

Other capillary malformation-overgrowth conditions

    CLOVES (another PROS condition) is named for its particular features: congenital lipomatous (fatty) overgrowth, vascular anomalies, epidermal nevi and scoliosis/skeletal/spinal anomalies. 
  • Proteus syndrome
    Proteus syndrome is a rare condition characterized by disorganized overgrowth of various tissues of the body caused by a mosaic variation in a gene called AKT1.
  • Diffuse capillary malformation with overgrowth (DCMO)
    DCMO is a rare condition characterized by vascular staining and tissue overgrowth and is caused by variants in the GNA11 or GNAQ genes. The symptoms of DCMO can be very difficult to distinguish from Klippel-Trenaunay syndrome, especially early in life.

Information about

Klippel-Trenaunay syndrome


No items found.

Content related to

No items found.
No items found.
No items found.