Clinical presentations of familial sarcoidosis: a retrospective cohort study from Finland

Familial sarcoidosis, a rare form of sarcoidosis involving multiple affected family members, is associated with a genetic predisposition.

This retrospective cohort study aimed to compare the clinical features, organ involvement, treatment and outcomes between familial and sporadic sarcoidosis in a well-defined Finnish population.

Data from 1130 patients with confirmed sarcoidosis diagnosed between 2008 and 2022 at Oulu University Hospital and Oulaskangas Hospital were analysed. Familial sarcoidosis was defined as disease occurring in at least one first-degree, second-degree or third-degree relative. Clinical characteristics, medication use and pulmonary function were compared between familial (n=68) and sporadic (n=1062) cases, with additional sex-specific analyses performed.

Familial sarcoidosis accounted for 6.0% of all confirmed cases and was more common in women and first-degree relatives. Compared with sporadic cases, familial sarcoidosis was associated with higher rates of ocular and renal involvement and more frequent multiorgan disease. Thoracic manifestations were equally common in both groups and pulmonary function over time was comparable between familial and sporadic sarcoidosis. Within the familial group, women had a trend towards more diverse extrapulmonary manifestations whereas men more frequently presented with concurrent pulmonary and lymph node involvement. There were no major sex-specific differences between familial and sporadic sarcoidosis patients.

These findings indicate that familial sarcoidosis in the Oulu region constitutes a clinically recognisable subtype within the disease spectrum, warranting systematic family history assessment and further clinical and genetic research.