What are DSI and DPI in DISGENET?

Disease Specificity Index (DSI) and Disease Pleiotropy Index (DPI) are metrics to help you refine your results in DISGENET.

Disease Specificity Index:
DSI quantifies the breadth of a gene or variant's disease associations. A high DSI indicates a gene or variant associated with a narrow set of diseases, while a low DSI suggests a broader range of associated diseases.

The DSI ranges from 0.23 to 1.

If the DSI is missing, it means the gene or variant is associated only with phenotypes.

Example of DSI:
TNF, associated with over 3,500 diseases, has a DSI of 0.23, indicating it is linked to a broad range of diseases. 

However, MOB3A, linked to a single disease, has a DSI of 1, indicating it is associated with a very narrow set of diseases.

Disease Pleiotropy Index:
DPI measures the similarity or diversity of diseases associated with a gene or variant based on MeSH disease classes. A low DPI indicates that the associated diseases are closely related within a specific MeSH class, while a high DPI suggests a wider range of unrelated diseases.

The DPI ranges from 0 to 1.

If the DPI is missing, it means the gene or variant is associated only with phenotypes or diseases that do not map to any MeSH classes.

Example of DPI:
KCNT1, associated with 39 diseases across 5 MeSH classes, has a DPI of ~0.172, suggesting it is linked to a diverse range of diseases. 

However, APOE, linked to over 700 diseases across 27 disease classes, has a DPI of 0.931, indicating high similarity among the associated diseases within specific MeSH classes.