Previous studies have demonstrated the prevalence of SFTPC mutations to be as high as 25% in familial pulmonary fibrosis (without a distinction from IPF, specifically) and as low as 0.7% in sporadic IPF.7, 8 The SFTPC mutations identified in our cohort have previously been identified in children and adults with ILD and/or IPF. This evidence concerns the gene SFTPC and interstitial lung disease.