user: What are the symptoms of Gardner syndrome ?

assistant: What are the signs and symptoms of Gardner syndrome? The signs and symptoms of Gardner syndrome vary from person to person. It is a form of familial adenomatous polyposis (FAP), which is characterized primarily by hundreds to thousands of noncancerous (benign) polyps in the colon that begin to appear at an average age of 16 years. Unless the colon is removed, these polyps will become malignant (cancerous), leading to early-onset colorectal cancer at an average age of 39 years. Other features of Gardner syndrome may include: Dental abnormalities Fundic gland or adenomatous polyps of the stomach Adenomatous polyps of the small intestines Osteomas (benign bone growths) Congenital hypertrophy of the retinal pigment epithelium (a flat, pigmented spot within the outer layer of the retina) Benign skin abnormalities such as epidermoid cysts, fibromas (a benign tumor of the connective tissue), and lipomas Adrenal masses Desmoid tumors Other types of cancer (small bowel, stomach, pancreas, thyroid, central nervous system, liver, bile ducts, and/or adrenal gland) The Human Phenotype Ontology provides the following list of signs and symptoms for Gardner 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) Adenomatous colonic polyposis 90% Intestinal polyposis 90% Duodenal polyposis 50% Neoplasm of the colon 50% Colon cancer 33% Multiple gastric polyps 33% Adrenocortical adenoma 13% Carious teeth 7.5% Congenital hypertrophy of retinal pigment epithelium 7.5% Delayed eruption of teeth 7.5% Epidermoid cyst 7.5% Fibroadenoma of the breast 7.5% Increased number of teeth 7.5% Irregular hyperpigmentation 7.5% Multiple lipomas 7.5% Neoplasm of the nervous system 7.5% Odontogenic neoplasm 7.5% Osteoma 7.5% Sarcoma 7.5% Unerupted tooth 7.5% Hepatoblastoma 1.6% Medulloblastoma 1% Duodenal adenocarcinoma % Papillary thyroid carcinoma % Adrenocortical carcinoma - Astrocytoma - Autosomal dominant inheritance - Hyperpigmentation of the skin - Keloids - Odontoma - Small intestine carcinoid - Variable expressivity - 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.