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Surfactant dysfunction
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Surfactant dysfunction

Surfactant dysfunction is a lung disorder caused by abnormalities in the surfactant mixture that lines the lungs, leading to severe breathing difficulties and respiratory distress.

Overview

Surfactant is a mixture of phospholipids and proteins that lines the lung tissue, preventing the air sacs (alveoli) from collapsing after exhalation. In surfactant dysfunction, this mixture is abnormal or insufficient, making it difficult to fill the lungs with air and impairing oxygen delivery. The severity ranges from life-threatening respiratory distress in newborns to gradual breathing problems in children and adults.

Symptoms

Symptoms vary based on the severity and type of the condition:

  • Newborns: Extreme difficulty breathing, inability to get enough oxygen, and potential organ damage. Most infants with the severe form do not survive beyond a few months.
  • Children and Adults: Abnormally rapid breathing (tachypnea), low concentrations of oxygen in the blood (hypoxemia), and failure to thrive (inability to gain weight at the expected rate).

Causes

The condition is caused by mutations in genes involved in the production and processing of surfactant. These proteins and fats are packaged in cellular structures called lamellar bodies before being released into the lungs.

  • SFTPB and SFTPC genes: Provide instructions for surfactant proteins B and C. Mutations lead to a lack of mature proteins, causing abnormal surfactant composition and function.
  • ABCA3 gene: Provides instructions for a protein that transports phospholipids into lamellar bodies. Mutations impair surfactant production and can lead to the accumulation of misfolded proteins, which may damage lung cells.

Associated Genes

  • ABCA3
  • SFTPB
  • SFTPC
  • CSF2RA
  • CSF2RB

Inheritance

Inheritance patterns vary by the specific genetic cause:

  • Autosomal recessive: Mutations in SFTPB or ABCA3 require both copies of the gene in each cell to be mutated.
  • Autosomal dominant: Mutations in SFTPC require only one copy of the altered gene to cause the disorder. These cases may be inherited from an affected parent or result from a new mutation in the individual.

Frequently Asked Questions

Most forms are autosomal recessive (ABCA3, SFTPB, SFTPC) or X‑linked (CSF2RA/CSF2RB). Parents should be offered carrier testing to determine recurrence risk (25 % for recessive, 50 % for X‑linked carrier mothers). Prenatal options include chorionic villus sampling or amniocentesis for targeted mutation analysis, and pre‑implantation genetic diagnosis (PGD) for families using IVF.
Patients may develop chronic interstitial lung disease with tachypnea, exercise intolerance, and progressive hypoxemia. High‑resolution CT often shows diffuse ground‑glass opacities and cystic changes. Pulmonary function tests reveal a restrictive pattern. Management shifts to long‑term oxygen therapy, antifibrotic agents, and monitoring for pulmonary hypertension.
Beyond the typical signs of respiratory distress, clinicians look for a lack of response to standard surfactant replacement and persistent hypoxemia. Diagnostic steps include bronchoalveolar lavage (BAL) showing lipid‑laden macrophages, chest CT with ground‑glass opacities, and definitive genetic testing for mutations in SFTPB, SFTPC, ABCA3, CSF2RA, or CSF2RB.
Infants with SFTPB deficiency do not benefit from conventional surfactant therapy because the protein is absent. Management focuses on aggressive respiratory support (high‑frequency ventilation, ECMO when needed) and early referral for lung transplantation, which is currently the only curative option. Some centers trial inhaled steroids or azithromycin to reduce inflammation, but evidence is limited.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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