Summary of previous studies on familial aggregation and heritability of sarcoidosis. Only familial aggregation studies with a control group were considered for this table

First author, year of publication [ref.]CountryProbands nRelatives nMean age at inclusion yearsSarcoidosis ascertainmentEstimates of familial aggregation/heritability
Headings, 1976 [11]USA80Prevalence estimate523 parents and full siblings34Not reportedBiopsy provenReported by probands7.2% of proband cases with ≥1 FDR with sarcoidosis
Heritability: 60–70%
McGrath, 2000 [17]UK406Prevalence estimateNot reported40Not reportedBiopsy and non-biopsy provenReported by proband, confirmed by family doctor5.9% of proband cases with ≥1 family member with sarcoidosis
Relative risk in siblings: 36–73
Rybicki, 2001 [15]USA70670610 862 FDRs
17 047 SDRs
42 (median)Not reportedBiopsy provenReported by probandOdds ratio in FDRs: 3.8 (1.9–7.6)
Odds ratio in SDRs: 5.2 (1.5–18.2)
Rybicki, 2001 [16]USA179Prevalence estimate and simulation488 parents and full siblings4366 in parents, 45 in siblingsBiopsy and non-biopsy provenReported by relativeRelative risk in FDRs: 2.5 (1.6–3.7)
Sverrild, 2008 [21]Denmark and Finland210NA210 twin pairs (50 MZ, 160 DZ)Not reportedNARegister-basedNAConcordance rates: 0.148 in MZ twins, 0.012 in DZ twins
Heritability: 66% (45–80%)

FDR: first-degree relative; SDR: second-degree relative; MZ: monozygotic; DZ: dizygotic; NA: not applicable.