Risk of bias and certainty of evidence were assessed using the JBI checklist for analytical studies and GRADE, respectively.<h4>Results</h4>In 19 eligible studies, circulating endostatin concentrations were significantly higher in SSc patients than controls (standard mean difference, SMD=0.90, 95% CI 0.56 to 1.23, p<0.001; low certainty of evidence). The gene discussed is COL18A1; the disease is systemic sclerosis.