No association of the HLA-DQ alleles with myasthenia gravis in Cuban patients.

Myasthenia gravis (MG) is a neuromuscular disorder characterized by fatigability and weakness of striated muscles. Its association with HLA molecules is well known and varies depending on age, sex and the ethnicity of the patients. A case-control study was performed in 61 Cuban patients and 81 controls using polymerase chain reaction and sequence-specific primers of the HLA-DQA1/B1 alleles. The distribution of the HLA-DQ alleles individually and in a simple haplotype between patients and controls shows no statistically significance differences. This result could be due to the heterogeneity and ethnic admixture existing in Cuban population. These findings indicate that the association between a disease and a particular genetic region cannot be explained merely by similarities in the genetic background but involve environmental and immunological factors.