Question: What is (are) Proteus syndrome ?
Answer: Proteus syndrome is characterized by excessive growth of a part or portion of the body. The overgrowth can cause differences in appearance and with time, an increased risk for blood clots and tumors. It is caused by a change (mutation) in the AKT1 gene. It is not inherited, but occurs as a random mutation in a body cell in a developing baby (fetus) early in pregnancy. The AKT1 gene mutation affects only a portion of the body cells. This is why only a portion of the body is affected and why individuals with Proteus syndrome can be very differently affected. Management of the condition often requires a team of specialists with knowledge of the wide array of features and complications of this condition.
Source: GARD

Question: What are the symptoms of Proteus syndrome ?
Answer: What are the signs and symptoms of Proteus syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for Proteus syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormal form of the vertebral bodies 90% Arteriovenous malformation 90% Asymmetry of the thorax 90% Decreased body weight 90% Irregular hyperpigmentation 90% Kyphosis 90% Lower limb asymmetry 90% Lymphangioma 90% Macrodactyly of finger 90% Melanocytic nevus 90% Multiple lipomas 90% Scoliosis 90% Skeletal dysplasia 90% Skeletal muscle atrophy 90% Tall stature 90% Bronchogenic cyst 50% Cafe-au-lait spot 50% Dolichocephaly 50% Finger syndactyly 50% Hyperkeratosis 50% Hypertelorism 50% Lymphedema 50% Macrocephaly 50% Pulmonary embolism 50% Visceral angiomatosis 50% Abnormality of dental enamel 7.5% Abnormality of immune system physiology 7.5% Abnormality of retinal pigmentation 7.5% Abnormality of the hip bone 7.5% Abnormality of the nail 7.5% Abnormality of the neck 7.5% Abnormality of the wrist 7.5% Anteverted nares 7.5% Arterial thrombosis 7.5% Atresia of the external auditory canal 7.5% Buphthalmos 7.5% Carious teeth 7.5% Cataract 7.5% Chorioretinal coloboma 7.5% Clinodactyly of the 5th finger 7.5% Cognitive impairment 7.5% Conjunctival hamartoma 7.5% Craniosynostosis 7.5% Depressed nasal bridge 7.5% Exostoses 7.5% Generalized hyperpigmentation 7.5% Hallux valgus 7.5% Heterochromia iridis 7.5% Hypertrichosis 7.5% Limitation of joint mobility 7.5% Long face 7.5% Long penis 7.5% Low-set, posteriorly rotated ears 7.5% Macroorchidism 7.5% Meningioma 7.5% Myopathy 7.5% Myopia 7.5% Neoplasm of the lung 7.5% Neoplasm of the thymus 7.5% Ovarian neoplasm 7.5% Polycystic ovaries 7.5% Proptosis 7.5% Ptosis 7.5% Reduced number of teeth 7.5% Renal cyst 7.5% Retinal detachment 7.5% Retinal hamartoma 7.5% Seizures 7.5% Sirenomelia 7.5% Splenomegaly 7.5% Strabismus 7.5% Sudden cardiac death 7.5% Talipes 7.5% Testicular neoplasm 7.5% Thymus hyperplasia 7.5% Calvarial hyperostosis - Deep venous thrombosis - Depigmentation/hyperpigmentation of skin - Epibulbar dermoid - Facial hyperostosis - Hemangioma - Hemihypertrophy - Hypertrophy of skin of soles - Intellectual disability, moderate - Kyphoscoliosis - Lipoma - Mandibular hyperostosis - Nevus - Open mouth - Spinal canal stenosis - Spinal cord compression - Sporadic - Thin bony cortex - Venous malformation - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Proteus syndrome ?
Answer: What causes Proteus syndrome? Proteus syndrome is caused by mutations in the AKT1 gene. This genetic change is not inherited from a parent; it arises randomly in one cell during the early stages of development before birth. As cells continue to grow and divide, some cells will have the mutation and others will not. This mixture of cells with and without a genetic mutation is known as mosaicism. The AKT1 gene helps regulate cell growth and division. (proliferation) and cell death. A mutation in this gene disrupts a cell's ability to regulate its own growth, allowing it to grow and divide abnormally. Increased cell proliferation in various tissues and organs leads to the abnormal growth characteristics of Proteus syndrome. Studies suggest that AKT1 gene mutations are more common in groups of cells that experience overgrowth than in the parts of the body that grow normally.
Source: GARD