PTGDR -441 C/T Polymorphism in a Mexican Mestizo Population with Inflammatory Myopathies: A Pilot Study

The prostaglandin D2 receptor (PTGDR) -441 C/T polymorphism has been previously associated with inflammatory diseases such as asthma. The goal of this study was to explore the association of this polymorphism with idiopathic inflammatory myopathies (IIM) and their clinical features. Seventy-two healthy subjects (HS) and forty-eight patients with IIM from Guadalajara and Mexico were recruited over three years. Clinical features and enzymes used for diagnostics and follow-up, such as creatine phosphokinase (CPK), lactate dehydrogenase (LDH), aspartate transaminase (AST), and alanine aminotransferase (ALT), were collected at the recruitment point and from the chart at the diagnostic point. PCR-ARMS was used to define genotypes. The Chi-square test was used to compare genotype and allele frequencies and clinical features between IIM patients and healthy subjects. A one-way ANOVA on ranks was performed to compare enzymatic levels. The allele distribution was not in Hardy-Weinberg equilibrium in the controls. There was no difference in age or gender distribution between the groups. The polymorphic (T) allele was more common in the IIM group than in the HS group. At the same time, the wild-type (CC) genotype presented more clinical features, such as heliotrope rash, fever, dyspnea, and weight loss, than the TT genotype. No significant differences were found regarding the enzyme levels. To further understand the role of this polymorphism in IIM, a bigger sample size is required along with mechanistical studies. Nevertheless, the polymorphic allele of the PTGDR -441 C/T polymorphism suggests susceptibility to IIM, whereas the wild-type CC genotype is associated with more clinical features.