Question: What is (are) Diabetes mellitus type 1 ?
Answer: Diabetes mellitus type 1 (DM1) is a condition in which cells in the pancreas (beta cells) stop producing insulin, causing abnormally high blood sugar levels. Lack of insulin results in the inability of the body to use glucose for energy and control the amount of sugar in the blood. DM1 can occur at any age, but usually develops by early adulthood, most often in adolescence. Symptoms of high blood sugar may include frequent urination, excessive thirst, fatigue, blurred vision, tingling or loss of feeling in the hands and feet, and weight loss. The exact cause of DM1 is unknown, but having certain "variants" of specific genes may increase a person's risk to develop the condition. A predisposition to develop DM1 runs in families, but no known inheritance pattern exists. Treatment includes blood sugar control and insulin replacement therapy. Improper control can cause recurrence of high blood sugar, or abnormally low blood sugar (hypoglycemia) during exercise or when eating is delayed. If not treated, the condition can be life-threatening. Over many years, chronic high blood sugar may be associated with a variety of complications that affect many parts of the body.
Source: GARD

Question: What are the symptoms of Diabetes mellitus type 1 ?
Answer: What are the signs and symptoms of Diabetes mellitus type 1? The Human Phenotype Ontology provides the following list of signs and symptoms for Diabetes mellitus type 1. 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) Abnormality of the immune system - Diabetes mellitus - Heterogeneous - Hyperglycemia - Ketoacidosis - Polydipsia - Polyphagia - Polyuria - 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