Hi All,
Fairly new to the vocab space within OHDSI 
I am a clinician/MD in rheumatology and interested in building rare disease cohorts in ATLAS, for the purposes of characterization and outcome studies.
One of the diseases I am interested in is IgG4-Related Diseases (IgG4-RD ; ICD 10 code D89.84). IgG4-RD is a multi-systemic inflammatory disease known for its various organ involvements: ex aorta, pancreatobiliary tract, orbits, thyroid, retroperitoneum…etc.
Just browsing on ATLAS, the only code corresponding to this condition is ID# 36716713 SNOMED “IgG4-related sclerosing cholangitis” (which would fall in the pancreatobiliary tract) which generates a RC/DRC of 0, and has no parents/children.
So having managed these cases, this one SNOMED code does not fully capture all the phenotypes of this complex disease.
To create a more comprehensive and representative cohort, would you suggest combining different sets of concepts? e.g. “aortitis” with “IgG4” and examine for overlaps?
Any advice would be appreciated. Thank you!
