Chinese lupus treatment and research group (CSTAR) registry: X. family history in relation to lupus clinical and immunological manifestations.

Objectives: This study aimed to examine the associations between family history and clinical manifestations and immunologic characteristics of lupus in China.

Methods: Based on their family history, lupus patients from the Chinese lupus treatment and research group (CSTAR) registry were categorised: familial lupus (FL), family history of other rheumatic disorders (RD), and sporadic lupus (SL). Demographic data, clinical manifestations, and laboratory data were compared among these three groups.

Results: A total of 2,104 patients from CSTAR were included, with 34 (1.6%) in the FL group, 50 (2.4%) in the RD group, and 2,020 (96.0%) in the SL group. There were no significant differences in age or gender among these groups (p=0.36 and p=0.75, respectively). The prevalence of discoid rash and positivity of anti-RNP antibodies differed significantly among the three groups. Photosensitivity and neurological disorder were marginally significantly different among the three groups (p=0.05). No statistical differences were observed in other clinical manifestations or laboratory results. In the FL group, first-degree relatives (25/34, 73.5%) had higher susceptibility to lupus. Rheumatoid arthritis (RA) (35/50, 70.0%) was the most frequent non-lupus rheumatic disorder in the RD group.

Conclusions: Among lupus patients, the rate of familial lupus was lower in Chinese patients than among other ethnicities. Familial lupus cases are found mainly among their first-degree relatives. A family history of lupus did not significantly affect clinical phenotypes, except for higher frequency of discoid rash and anti-RNP in the FL group, and more anti-RNP positivity in the RD group.