BACKGROUND: Distinct mutations of the caspase activating recruitment domain 15 (CARD15) gene (also known as nucleotide-binding oligomerisation domain protein 2) on chromosome 16q are associated with the chronic granulomatous disease called Blau syndrome. Sarcoidosis is a systemic granulomatous disease, which has features in common with Blau syndrome.

AIM: The aim of this study was to evaluate whether ethnic Danes with sarcoidosis have CARD15 mutations associated with Blau syndrome.

METHODS: Analysis of exon 4 of the CARD15 gene containing mutations associated with Blau syndrome was performed by polymerase chain reaction and sequencing of genomic DNA from 52 patients with histologically verified sarcoidosis.

RESULTS: None of the patients had mutations in CARD15 associated with Blau syndrome. Eight other variations were found in exon 4: single nucleotide polymorphism (SNP)6 in 40% of the 104 alleles examined, SNP7 in 26%, c. 1833 C > T and SNP8 in 4%, c. 2107 C > T in 2%, and c. 931 C > T, c. 1292 C > T and c. 2377 G > A in 1%. One variation was found in intron 4 (IVS4 + 10 A > C) in 3% of the alleles. The frequencies of the variations in sarcoidosis patients were not statistically significant compared with frequencies in a control group of 103 healthy subjects. The course of disease was not significantly different in patients with or without variations in CARD15 or in the 46 patients with SNP6 and/or SNP7.

CONCLUSIONS: Danish sarcoidosis patients have frequent variations in CARD15 exon 4, but do not present any mutation associated with Blau syndrome. The variations found had no influence on the course of disease.