Background: The most common disease-associated mutation in AATD is PI*Z which determines increased risk of lung disease (pulmonary emphysema, asthma and bronchiectasis). PISZ and PIMZ result in less severe phenotype than PIZZ. Initial evaluation and follow up measurement of lung function are required to evaluate disease progression.

Aims and objectives: Spirometry is commonly used for monitoring lung function, although initial manifestation of emphysema cannot be identified by forced expiratory maneuvers. If a plethysmography test is not available, as in preschool children, it is important to consider other diagnostic tools.

Methods: 3 patients (2 males and 1 female) diagnosed with AATD, in follow up at our Pediatric Department, were included.

Results: Patient 1 presented pulmonary symptoms (recurrent cough and acute bronchitis) at the age of 3. Blood test detected AATD. His allelic genotype resulted PISZ. AAT was first suspected in his sister when at the age of 8 she had obstructive rhinitis. She was discovered to have the same allelic genotype of his brother. Patient 3 experienced recurrent episodes of bronchopneumonia since the age of 5. He was diagnosed with AATD with PIMZ genotype. Only 1 out of 3 has never presented any asthmatic symptoms. The lung function parameters (FEV1, FVC e TLC) have been always in range in all patients.

Conclusions: A normal spirometry does not exclude presence of AATD related lung disease even in genotypes other than PIZZ with high risk to develop severe emphysema during adulthood compared to other PI-types. Furthermore, there should be a greater awareness of this disease among pediatricians, especially it is mandatory to test AT level with a suggestive clinic or positive family history.