Klippel-Trenaunay syndrome (KTS) is a rare disorder that is present at birth (congenital) and is characterized by a triad of cutaneous capillary malformation (“port-wine stain”), lymphatic anomalies, and abnormal veins in association with variable overgrowth of soft tissue and bone. KTS occurs most frequently in the lower limb and less commonly in the upper extremity and trunk.
Klippel-Trenaunay Syndrome is a congenital, vascular disorder affecting one or more limbs. Klippel-Trenaunay Syndrome was first noted in a 1900 publication of Archives Generales de Medecine. In the article, Du Naevis Variquex, Osteo-Hypertrophique, French physicians Klippel and Trenaunay described a clinical syndrome with three major symptoms (Gloviczki, 1982).
These main symptoms are often referred to as the “triad.” The triad consists of hemangiomas, bone and soft tissue hypertrophy, and vein varicosities. Hemangiomas are often apparent at birth, or by two weeks of age (Samuel, 1995). The hemangioma, or nevus, is usually confined to a part of the limb. In other cases, the entire limb is affected by the hemangioma (Samuel, 1995). Capillary hemangiomas are the most common type and are called port wine stains due to the red and purple color (Letts, 1977). Bone and soft tissue hypertrophy is a result of increased growth around an organ. In many cases, limb length is affected and t he length of the limb is different than the normal limb.
The soft tissue hypertrophy is symmetrical around the affected extremity. In most cases, the girth of the limb is larger, although atrophy is common in some patients. Varicose veins are often very noticeable in Klippel-Trenaunay Syndrome patients. Varicose veins result from damaged or defective valves in a vein. A vein becomes damaged when the smooth muscle in the wall of veins weakens and the valves cannot support the weight of blood. The pressure on the valve causes it to collapse and it no longer functions properly. Klippel-Trenaunay Syndrome patients are affected by other symptoms as well.
These symptoms are variably expressed and may not have identical effects on other patients. Each case of KTS is unique.
In 1907, Parkes and Weber described a disorder with the same symptoms involved in Klippel-Trenaunay Syndrome with the addition of arteriovenous fistula. This derivative of Klippel-Trenaunay Syndrome was called Klippel-Trenaunay-Weber Syndrome. More information is available about KTS on the NIH site.
A mutation in the PIK3CA gene is considered the cause of KTS. This mutation occurs in primitive cells of blood and lymphatic vessels, fat, and bones, of the affected limb.
Learn more about how we can help families affected by KTS to pay for travel expenses related to its diagnosis and/or treatment: Brian C. Weber Memorial Travel Fund for KTS families.