When abnormalities such as vascular malformation, capillary arteriovenous malformations (AVMs), arteriovenous fistulas (AVFs) and overgrowth of a limb occur together in combination and disturb the complex network of blood vessels of the vascular system, it is known as PWS.

In some cases, PWS is a genetic condition where the RASA1 gene is mutated and displays an autosomal dominant inheritance pattern.

"Port-wine stain" or discoloration of the skin due to vascular malformation is also referred as nevus flammeus.

[9] These irregular connections affect the blood circulation and may lead to life-threatening complications such as abnormal bleeding and heart failure.

AVFs can be identified by: large, purplish bulging veins, swelling in limbs, decreased in blood pressure, fatigue and heart failure.

[10] The Human Phenotype Ontology (HPO) reports of additional symptoms in PWS patients.

HPO is an active database that collects and researches on the relationships between phenotypic abnormalities and biochemical networks.

According to HPO, the symptoms which are reported very frequently in PWS patients include: abnormal bleeding, hypertrophy of the lower limb, hypertrophy of the upper limb, nevus flammeus or staining of the skin, peripheral arteriovenous fistula, telangiectasia of the skin.

Frequent to occasional symptoms include: varicose veins, congestive heart failure, glaucoma and headache.

The cardiac output is decreased and the amount of blood pumped is not adequate enough to keep the circulation from the body and lungs going.

[6] This means that one copy of the damaged or altered gene is sufficient to elicit PWS disorder.

According to Boston's Children Hospital, no known food, medications or drugs can cause PWS during pregnancy.

However, according to NIH Genetics Home Reference, it is still unclear how exactly the disruption of p120-RasGAP protein formation leads to vascular abnormalities and limb overgrowth.

But it is a known fact that somehow p120-RasGAP protein is crucial for the normal development of the vascular system and its complex network of blood vessels such as arteries, veins and capillaries.

[19] Based on current knowledge, disruption of p120-RasGAP protein is the reason behind blood vessel malformations which in turn lead to all sorts of problems such as: overgrowth in limbs, excess blood flow near the surface of the skin which leads to port wine stains and even heart failure can occur.

So the doctors and other healthcare professions rely on the person's medical history, the severity of the symptoms, physical examination and lab tests to make and confirm a diagnosis.

[21] Usually a specific set of symptoms such as capillary and arteriovenous malformations occur together and this is used to distinguish PWS from similar conditions.

[12] PWS can be distinguished from other conditions because of its defining port-wine stains that are large, flat and pink.

The following tests may be ordered by physicians to help determine the appropriate next steps: MRI, ultrasound, CT/CAT scan, angiogram, and echocardiogram.

[22] Echocardiogram: depending on the intensity of the PWS syndrome, an echo could also be ordered to check the condition of the heart.

Embolization includes a substance injected by an interventional radiologists that can help in the elimination of the abnormal connections between the arteries and veins.

[23] According to "Parkes Weber syndrome—Diagnostic and management paradigms: A systematic review", published in July 2017, embolization alone or in combination with surgical removal of arteriovenous malformations leads to significant clinical improvement.

[26] Laser therapy can also help lighten capillary malformations and can speed up the healing process of the bleeding lesions.

[23] Physical therapists can help ease the pain and increase the range of movements of the arm or leg that is overgrown.

The classic port-wine stains may make the patient feel uncomfortable and counselors can help with the psychological and social issues.

[27] The purpose of the study is to assess how the port-wine stains can lead to complex syndromes such as PWS.

Also, embolization along with surgical resection that targets arteriovenous malformations reliably leads to significant clinical improvements.