The christmas disesase patient lacks antihaemophilic

Options

A. Homogentisic acid oxidase
B. Factor VIII
C. Factor XI
D. Factor IX

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that a patient with Christmas disease lacks antihaemophilic factor. We need to identify which clotting factor is deficient in this condition.

2. **Identifying Christmas Disease**: Christmas disease is another name for Hemophilia B. It is important to recognize that this condition is related to a deficiency in a specific clotting factor.

3. **Clotting Factors Overview**: There are several clotting factors involved in the blood coagulation process. The most relevant ones mentioned in the options are:
- Factor VIII
- Factor IX
- Factor XI

4. **Differentiating Hemophilia Types**:
- **Hemophilia A**: Caused by a deficiency of Factor VIII.
- **Hemophilia B (Christmas Disease)**: Caused by a deficiency of Factor IX.
- **Hemophilia C**: Caused by a deficiency of Factor XI.

5. **Conclusion**: Since Christmas disease is specifically associated with a deficiency in Factor IX, we conclude that the patient lacks this particular clotting factor.

### Final Answer:
The patient with Christmas disease lacks **Factor IX**.

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