Related Experiment Video
Updated: Oct 8, 2025
Refined Murine Model of Idiopathic Pulmonary Fibrosis
Published on: June 17, 2025
Pulmonary Alveolar Microlithiasis - A Review
Asbjørn Enemark1, Åsa Lina M Jönsson2, Sissel Kronborg-White3,4
1Department of Pulmonology, Aalborg University Hospital, Aalborg, Denmark.
Abstract:
Pulmonary Alveolar Microlithiasis (PAM) is a rare genetic disorder causing widespread deposition of calcium-phosphate crystals in the alveolar space. A hallmark of the disease is the discrepancy between perceived symptoms upon diagnosis compared with the extensive, sandstorm-like appearance of the microliths on chest X-ray or HRCT. Caused by a defective sodium-dependent phosphate transport protein due to loss-of-function variants of the SLC34A2 gene, PAM is an autosomal recessive transmitted disorder, and as such has a high correlation to consanguinity. The most common variants of the SLC34A2 gene are single nucleotide biallelic changes, but larger deletions are described. Initial suspicion of PAM on radiological examination should be followed by genetic testing to verify the diagnosis and identify the disease-causing variant. When not available, the diagnosis can be made by means of invasive techniques, such as transbronchial forceps or cryobiopsy, or a surgical lung biopsy. In families with a history of PAM, genetic counseling should be offered, as well as preimplantation/prenatal testing if necessary. As of writing this review, no definitive treatment exists, and PAM may in some cases progress to severe pulmonary disease with respiratory failure and potential death. Patients with PAM should be offered preventative and symptomatic treatments such as vaccinations and oxygen therapy when needed. In some cases, lung transplantation may be required.
Insights
Pulmonary Alveolar Microlithiasis (PAM) is a rare genetic lung disease caused by SLC34A2 gene variants. Diagnosis involves genetic testing, and while no cure exists, supportive care and lung transplantation are options.
Area of Science:
- Pulmonary Medicine
- Genetics
- Rare Diseases
Background:
- Pulmonary Alveolar Microlithiasis (PAM) is a rare genetic disorder characterized by calcium-phosphate crystal deposition in lung alveoli.
- A key feature is the disparity between mild symptoms and extensive radiographic findings, often described as a 'sandstorm' appearance.
- PAM results from loss-of-function variants in the SLC34A2 gene, encoding a phosphate transporter, and is inherited in an autosomal recessive pattern, frequently associated with consanguinity.
Purpose of the Study:
- To review the key aspects of Pulmonary Alveolar Microlithiasis (PAM).
- To highlight diagnostic approaches, including genetic testing and invasive procedures.
- To discuss current management strategies and prognosis for patients with PAM.
Main Methods:
- Review of existing literature on Pulmonary Alveolar Microlithiasis.
- Analysis of diagnostic criteria and genetic underpinnings.
- Summarization of therapeutic interventions and outcomes.
Main Results:
- PAM is caused by biallelic variants in SLC34A2, with single nucleotide changes being most common.
- Diagnosis is confirmed by genetic testing; invasive biopsies can be used if genetic testing is unavailable.
- No definitive cure exists; management focuses on supportive care, vaccinations, oxygen therapy, and potentially lung transplantation.
Conclusions:
- Early diagnosis of PAM through genetic testing is crucial.
- While no cure is available, symptomatic management and lung transplantation can be considered.
- Genetic counseling and prenatal testing are important for affected families.
