Klippel-Trenaunay Syndrome

Klippel-Trenaunay syndrome (KTS) is a congenital deformity characterized by the improper development of soft tissues, bone, blood, and lymph vessels. KTS manifests as a red birthmark, called a "port-wine stain, " commonly found on the face.

Last Updated: February 23, 2024

The birthmark may first appear as a flat, smooth, pink, or red spot on a newborn. It could enlarge, darken, and thicken up with time.

Experts estimate about 1 in every 100,000 people suffer from KTS. It was also observed that this disorder typically occurs with the same frequency in both sexes.

Usually, KTS results from a mutation in the PIK3CA gene, but this alteration is intermittent (for no known reason), meaning it is not inherited from a parent. However, not everyone with KTS has a PIK3CA mutation.

People with KTS usually have the following:

  • Hemangiomas (benign tumors that develop on the skin and are made up of clusters of blood vessels) and varicose veins; 
  • Fused toes and fingers, and there may even be some extra ones;
  • Vessel abnormalities in the digestive tract, genitourinary tract, genitourinary tract, hepatic vena cava, splenic vena cava, urinary bladder, kidney, lung, and heart --causing internal bleeding.
  • Highly vulnerable to developing blood clots.


Sturge-Weber syndrome is a disorder that is similar to port-wine stains. People with Sturge-Weber syndrome have abnormal blood vessels on their faces and brains. Because of this similarity, KTS patients may have epilepsy and mental retardation. 

Parkes-Weber syndrome is another condition where its manifestations overlap with KTS. It is characterized by aberrant arterial and venous connections (arteriovenous fistulas).

Initial diagnoses of KTS are made based on physical manifestations. The presence of many KTS symptoms before delivery means a diagnosis of KTS may be made prenatally.

Potential diagnostic procedures for Klippel-Trenaunay syndrome include the following:

  • Imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) can reveal information about the organs, muscles, and bones;
  • Imaging of blood arteries and veins using magnetic resonance (MR) angiography;
  • Examining blood flow in the veins and arteries may be done with a color Doppler ultrasonography. 


Depending on the symptoms, Klippel-Trenaunay syndrome may be treated in different ways. Therapies include:

  • Anticoagulants like heparin to lower the risk of blood clots in the legs and lungs;
  • Compression socks return blood to the heart. These reduce swelling, pain, and the risk of blood clots;
  • Endovenous thermal ablation uses energy beams to seal off defective veins
  • Laser therapy to lighten port-wine birthmarks;
  • Sclerotherapy involves injecting a fluid into veins or lymphatic channels to seal them.; 
  • Surgery for vein issues or uneven leg length.

KTS is impossible to prevent because its occurrence is random.



National Institute of Neurological Disorders and Stroke (2022). Klippel-Trenaunay Syndrome (KTS). Retrieved December 19, 2022, from https://www.ninds.nih.gov/health-information/disorders/klippel-trenaunay-syndrome-kts


Cleveland Clinic (2022). Klippel-Trenaunay Syndrome. Retrieved December 21, 2022, https://my.clevelandclinic.org/health/diseases/17152-klippel-trenaunay-syndrome-kts


Cleveland Clinic (2022). Port Wine Stain. Retrieved December 21, 2022, https://my.clevelandclinic.org/health/diseases/24389-port-wine-stain

Last Updated: February 23, 2024