Association of Down syndrome and segmental tracheal stenosis with ring tracheal cartilages: a review of nine cases.

Four patients with Down syndrome and midtracheal stenosis, three with proven absence of the midtracheal pars membranacea ("hourglass trachea"), are reported. Five previously reported patients who had Down syndrome and tracheal stenosis of this type are summarized. Respiratory difficulty and stridor were the reported clinical features of all but one of the patients whose clinical story is available. That approximately half the patients with tracheal stenosis with hourglass trachea and midtracheal absence of the tracheal pars membranacea reported had Down syndrome suggests that the association of this pattern of congenital tracheal stenosis with Down syndrome is, although infrequent, significant.