Congenital alveolar capillary dysplasia

Congenital alveolar capillary dysplasia (ACD), also known as alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV), is a rare and typically fatal developmental disorder of the lungs. In this condition, the tiny blood vessels (capillaries) in the lungs fail to develop properly and are reduced in number and abnormally positioned relative to the air sacs (alveoli). Additionally, the pulmonary veins are often misaligned, running alongside the pulmonary arteries and bronchioles rather than in their normal position within the connective tissue between lung lobules. This structural abnormality severely impairs gas exchange, preventing adequate oxygen from reaching the bloodstream. Affected newborns typically present within the first hours to days of life with severe, refractory pulmonary hypertension (high blood pressure in the lung arteries) and profound hypoxemia (low blood oxygen levels) that does not respond to conventional therapies, including supplemental oxygen, mechanical ventilation, inhaled nitric oxide, or extracorporeal membrane oxygenation (ECMO). Symptoms include respiratory distress, cyanosis (bluish discoloration of the skin), and rapid clinical deterioration. Many affected infants also have associated congenital anomalies involving the cardiovascular, gastrointestinal, and genitourinary systems, as well as the spleen. ACD/MPV is most commonly caused by mutations in the FOXF1 gene on chromosome 16q24.1, or by deletions involving this genomic region. The condition can occur as a de novo (new) mutation or be inherited. Currently, there is no effective medical treatment for ACD/MPV, and the condition is almost uniformly lethal in the neonatal period. Lung transplantation has been attempted in rare cases but outcomes remain very poor. Diagnosis is often confirmed by lung biopsy or autopsy. Genetic testing and counseling are recommended for affected families, as some cases involve inherited genomic imbalances with recurrence risk.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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