The evaluation of the SMAD1 rs1016792 polymorphism and gene expression on pulmonary hypertension due to congenital heart disease in children: a preliminary study

Smad Family Member (SMAD), a protein family responsible for transducing the signal induced by TGF-β into the nucleus, is thought to play a role in the pathology of many heart diseases. Therefore, we aimed to evaluate the influence of the SMAD1 rs1016792 polymorphism and gene expression on pulmonary arterial hypertension (PAH) due to congenital heart disease (CHD) in children. A total of 90 children, 45 of whom were PAH-CHD children and 45 healthy children, were included in the study. Patients were selected from those who were diagnosed and followed in the Department of Pediatric Cardiology.The SMAD1 rs1016792 genotyping and expression analysis was performed using a real-time polymerase chain reaction (RT-PCR)-based system. It was determined that the left ventricular end-diastolic diameter (LVEDD) value was lower in the patient group than in the control group, while the pulmonary artery pressure (PAP) value was higher in the patient group than in the control group. When the SMAD1 gene expression level was examined, a statistically significant difference was found between the patient and control groups. Patients had decreased SMAD1 expression compared to controls (p˂0.001). We found no significant difference between the patient and control groups in terms of SMAD1 rs1016792 genotype distribution or allele frequency (p > 0.05). There was no difference between genotype distribution and SMAD1 expression levels in the groups. In this study, we showed for the first time that SMAD1 expression is decreased in children with PAH-CHD. These results will be a preliminary step toward understanding the role of SMAD1 in the etiopathogenesis of CHD.