Comparison of sarcoidosis phenotypes among affected African-American siblings.
OBJECTIVE
To test the hypothesis that sibling pairs, who share genes and environmental exposures, might have similar phenotypic expressions of sarcoidosis beyond what would be expected by chance alone.


METHODS
Multicenter family study with study subjects recruited from 11 clinical centers.


METHODS
Subjects were African-American sibling pairs with sarcoidosis. Sarcoidosis and organ pattern involvement were defined according to specific criteria. Fifteen different organ systems were evaluated.


RESULTS
For full-sibling pairs, ocular involvement was found in both siblings more often than expected by chance alone (p < 0.05), but the concordance was weak (kappa = 0.18). When analyzing full-sibling and half-sibling pairs, ocular and liver involvement showed a significant concordance between sibling pairs (p < 0.05), but again the agreement was poor (kappa = 0.16 for both). Concordance in pulmonary function change over time was also weak. Clinical outcomes of sibling pairs were not significantly correlated except for whether treatment was prescribed, and this level of agreement was poor (kappa = 0.14 for full-sibling and half-sibling pairs; kappa = 0.15 for full-sibling pairs only). Modeling phenotypic expression in sibling pairs using logistic regression did show that the presence of ocular and liver sarcoidosis in the first affected sibling conferred a statistically significant increased risk to the second affected sibling for having those organs involved (odds ratio [OR], 3; 95% confidence interval [CI], 1.7 to 5.4 for ocular; OR, 3.3; 95% CI, 1.5 to 7.4 for liver).


CONCLUSIONS
The phenotypic features and clinical outcomes of sarcoidosis in sibling pairs show minimal concordance, with the possible exception that the presence of ocular or liver involvement in the first sibling with a diagnosis of sarcoidosis makes involvement of these organs more likely in other affected siblings.
Judson
Marc A
MA
Division of Pulmonary and Critical Care Medicine CSB-812, Medical University of South Carolina, Charleston, SC 29425, USA. judsonma@musc.edu
Hirst
Kathryn
K
Iyengar
Sudha K
SK
Rybicki
Benjamin A
BA
El-Ghormli
Laure
L
Baughman
Robert P
RP
Donohue
James F
JF
Elston
Robert C
RC
Kavuru
Mani S
MS
Moller
David R
DR
Newman
Lee S
LS
Rabin
David L
DL
Rossman
Milton D
MD
Teirstein
Alvin S
AS
Iannuzzi
Michael C
MC
D000328:Adult; D001741:Black or African American / Q000235:genetics*; D000368:Aged; D004781:Environmental Exposure; D005123:Eye / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D012507:Sarcoidosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D035781:Siblings