Question: What is (are) Warfarin sensitivity ?
Answer: Warfarin sensitivity is a condition that is characterized by a reduced tolerance for a "blood-thinning" medication called warfarin. Warfarin is an anticoagulant that is often prescribed to people who are at an increased risk for blood clots. People with a warfarin sensitivity respond more strongly to lower doses of warfarin and are, therefore, more likely to experience an overdose or other serious side effects from the medication. They may experience abnormal bleeding in the brain, gastrointestinal tract, or other tissues even at average doses. The metabolism of warfarin and the drug's effects in the body are complex traits that are determined by several genes as well as environmental and lifestyle factors such as gender, age, weight, diet, and other medications. Two specific genetic polymorphisms in the CYP2C9 and VKORC1 genes account for approximately 30-40% of variation in the response to warfarin and can be passed on to future generations in an autosomal dominant manner.
Source: GARD

Question: What are the symptoms of Warfarin sensitivity ?
Answer: What are the signs and symptoms of Warfarin sensitivity? The Human Phenotype Ontology provides the following list of signs and symptoms for Warfarin sensitivity. 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 blood and blood-forming tissues - Abnormality of metabolism/homeostasis - Autosomal dominant inheritance - 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