Genetic Risk Factors for aPL Syndrome

MHC class II alleles and C4 deficiency alleles have been variably associated with aPL syndrome, but the extensive linkage disequilibrium among many of these alleles has made it difficult to assign a causal role for any of them. Interethnic studies of these and other alleles in large cohorts of subjects would help to clarify the roles of these alleles in aPL syndrome.