Familial clustering of systemic lupus erythematosus in the cayman islands.

Objective: To describe the unusual clustering of systemic lupus erythematosus (SLE) in a family from the Cayman Islands.

Method: An observational retrospective study of SLE was done following an index case of mixed connective tissue disease in a 51-year old West Indian woman of African descent. Her two daughters of the same father, who is of Cayman Islands origin, were also diagnosed with SLE. A family tree was subsequently drawn up to 1890 to identify other cases in the same family.

Results: There were 13 cases identified and all occurred between the 6th and the 8th generation. A family tree linked all cases to a man from the Cayman Islands who died in 1890. The nine cases with full medical records showed eight females and one male (8:1). The mean age at diagnosis was 29 years; polyarthritis occured in all nine patients (100%), kidney involvement in 6/9 (66.6%), skin rash in 6/9 (66.6%), pleuritis and pericarditis in 6/9 (66.6%) and anaemia in 6/9 (66.6%). The autoantibodies were mainly ANA in all patients (100%) and anti-dsDNA in 8/9 (88.8%).

Conclusion: The unusual extensive familial clustering in this study represents the first to be described in a West Indian population where SLE is most prevalent and may suggest a genetic predisposition.