Although a deficiency of alpha-1 antitrypsin, which is an inhibitor of enzymes that break down proteins, may seem like a simple cause of chronic obstructive pulmonary disease (COPD), the genetic basis behind the deficiency can be quite varied. A research group from the University of Munich in Germany treated a 44-year-old woman previously diagnosed with COPD for bronchiectasis as a result of a new cause of alpha-1 antitrypsin deficiency.

The researchers wrote about their case study in the article, “Identification of a Novel SERPINA-1 Mutation Causing Alpha-1 Antitrypsin Deficiency in a Patient with Severe Bronchiectasis and Pulmonary Embolism,” which was published in International Journal of Chronic Obstructive Pulmonary Disease. The patient was diagnosed with COPD 9 years before admission to the emergency department, where she visited due to concerns over shortness of breath and respiratory insufficiency. After a chest computed tomography scan, the doctors diagnosed her with bronchiectasis.

Delving into the reason for her bronchiectasis, the researchers identified a genetic mutation in the SERPINA-1 gene. It was surprising to find this mutation rather than a mutation in CFTR because the patient showed symptoms consistent with a diagnosis of cystic fibrosis. Instead, the patient had the first known SERPINA-1-associated alpha-1 antitrypsin deficiency due to a mutation in exon 2 of the gene.

Usually, patients with alpha-1 antrypsin deficiency have a “Z” or “S” mutation in SERPINA-1, where the Z mutation leads to significantly lower levels of alpha-1 antitrypsin than those seen with the S mutation. By recognizing a new cause of disease, the researchers may be better prepared for diagnosing future patients who present with these symptoms but with none of the typical gene mutations.

To treat the patient, the doctors chose to administer oxygen therapy and oral ciprofloxacin. The patient was also instructed to inhale colistin twice daily. This treatment was intended to clear her infection with Pseudomonas aeruginosa, although the primary cause of disease was alpha-1 antitrypsin deficiency. “The atypical presentation of the patient, with severe cystic bronchiectasis, highlights alpha-1 antitrypsin deficiency as a differential diagnosis in bronchiectasis,” stated the authors. In other words, underlying mutations may be overlooked by a simple diagnosis of bronchiectasis, and greater awareness of these differential diagnoses is needed.