The Revised Ghent criteria calculator evaluates whether a patient meets the diagnostic criteria for Marfan syndrome based on a structured set of criteria inputs. The calculator considers family history, aortic root diameter, presence of ectopia lentis, systemic score, and the presence of an FBN1 pathogenic variant.

The diagnostic process involves the following:

1. Family History of Marfan Syndrome:
   - Yes
   - No

2. Aortic Root Diameter (Z score):
   - >= 2 (or >= 3 in individuals under 20 years old with a family history)
   - < 2

3. Ectopia Lentis:
   - Yes
   - No

4. Systemic Score:
   - >= 7
   - < 7

5. FBN1 Pathogenic Variant:
   - Positive
   - Negative

The conditions for meeting the diagnostic criteria are evaluated as follows:

For patients without a family history of Marfan syndrome:
- The criteria are met if there is an aortic root diameter of >= 2 along with either ectopia lentis, a systemic score >= 7, or a positive FBN1 pathogenic variant. Combinations of any two or more of these features (e.g., ectopia lentis and FBN1 pathogenic variant, ectopia lentis and systemic score >= 7, etc.) along with the aortic root diameter can also establish a diagnosis.
- Alternatively, the criteria are met if both ectopia lentis and a positive FBN1 pathogenic variant are present, regardless of other criteria.

For patients with a family history of Marfan syndrome:
- The criteria are met with any one of aortic root diameter >= 2, ectopia lentis, or systemic score >= 7. Any combination of two or more of these features also confirms a diagnosis.

The output is a simple result indicating whether the "Diagnostic criteria are met" or "Diagnostic criteria are not met" based on the inputs provided. If an input is missing, the result prompts the user to "Please make a selection for all inputs."

The Revised Ghent Criteria is a diagnostic tool used for the identification of Marfan Syndrome, a genetic disorder affecting the body's connective tissue. This calculator is applicable to individuals of all ages who are suspected of having Marfan Syndrome based on clinical features, family history, or genetic testing. 

The Revised Ghent Criteria provides a systematic approach to diagnose Marfan Syndrome by evaluating various clinical manifestations in the skeletal, ocular, cardiovascular systems, and considering the family history and FBN1 gene mutations. 

The clinical utility of this calculator lies in its ability to accurately diagnose Marfan Syndrome, which is crucial for appropriate management and treatment of the condition. Early diagnosis can help prevent or manage potential complications such as aortic dissection or rupture, which can be life-threatening.

There are no specific exclusion criteria for the use of the Revised Ghent Criteria. However, it should be noted that this calculator is not designed to diagnose other connective tissue disorders that may present with similar symptoms to Marfan Syndrome. Therefore, a negative result does not rule out other connective tissue disorders.

Revised Ghent criteria for diagnosis of Marfan syndrome