Outline
Disclosed is an in vitro method for diagnosing susceptibility to post-traumatic scar tissue formation, wherein from a biological sample of a patient the nucleotide of the -509 position of the TGF-βl gene is determined and if said -509 position contains exclusively C, thus it is the homozygotic wild type allele, then said patient is considered to be susceptible to post- traumatic scar tissue formation. The invention relates furthermore to diagnostic kits for the detection of susceptibility to post-traumatic scar tissue formation, preferably for the detection of susceptibility to tracheal stenosis from a biological sample.