A major deletion in the surfactant protein-B gene causing lethal respiratory distress

Acta Paediatr. 2007 Apr;96(4):516-20. doi: 10.1111/j.1651-2227.2006.00188.x.


Background: Loss of function mutations in the surfactant protein-B gene (SFTPB) cause lethal neonatal respiratory distress due to reduced or absent expression of mature surfactant protein B (SP-B, encoded in exons 6 and 7). No large deletions in SFTPB have been previously identified.

Aim: Genomic, proteomic and immunohistochemical characterization of a 3 kb deletion in SFTPB.

Methods: A full-term newborn presented with refractory respiratory failure. We amplified and sequenced SFTPB from the infant and both parents, determined SP-B protein expression in tracheal aspirate samples using Western-blot analysis, and performed immunohistochemical staining and electron microscopy of lung biopsy tissue.

Results: The infant was homozygous for a 2958 bp deletion in SFTPB that included exons 7 and 8. Both asymptomatic parents were heterozygous for the deletion. A truncated mature SP-B peptide was detected on Western blotting of tracheal aspirate. Amino acid sequence specific to that encoded in exon 5 was present, but that encoded by exon 7 was absent. ProSP-B expression was robust within alveolar type II cells and lamellar body structure was disrupted.

Conclusions: This deletion in SFTPB resulted in SP-B deficiency due to absence of elements in mature SP-B that are critical for appropriate peptide folding, trafficking and processing.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural

MeSH terms

  • Base Pairing / genetics
  • Fatal Outcome
  • Female
  • Gene Deletion*
  • Humans
  • Infant, Newborn
  • Pulmonary Surfactant-Associated Protein B / genetics*
  • Respiratory Distress Syndrome, Newborn / genetics*


  • Pulmonary Surfactant-Associated Protein B