Overview
Pulmonary alveolar microlithiasis (PAM) is a rare lung disease where tiny calcium-containing stones, called microliths, slowly build up inside the air sacs (alveoli) of the lungs. These deposits are so small they can only be seen under a microscope, but over time they can fill the lungs and make it harder to breathe. The disease is also sometimes called microlithiasis alveolaris pulmonum. PAM is caused by changes (mutations) in the SLC34A2 gene, which normally helps control phosphate levels in the lungs. When this gene does not work properly, phosphate builds up and forms calcium-phosphate crystals inside the air sacs. Many people with PAM have no symptoms for years or even decades, especially in childhood. As the disease progresses, the most common symptoms are shortness of breath, a chronic cough, and reduced ability to exercise. The lungs gradually become stiffer and less able to transfer oxygen into the blood, which can eventually lead to respiratory failure. There is currently no approved cure or disease-modifying treatment for PAM. Care focuses on managing symptoms, supporting breathing, and monitoring lung function over time. In advanced cases, lung transplantation has been performed and can be life-saving. Research into targeted therapies is ongoing, giving hope for future treatments.
Key symptoms:
Shortness of breath, especially with activityChronic dry coughReduced ability to exercise or walk without getting windedChest tightness or discomfortFatigue and low energyLow oxygen levels in the bloodBluish tint to lips or fingertips (cyanosis) in advanced diseaseClubbing of the fingers (fingertips become rounded and enlarged)Frequent respiratory infectionsCrackling sounds in the lungs heard by a doctor
Clinical phenotype terms (43)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Variable
Can begin at different ages, from infancy through adulthood
Treatments
No FDA-approved treatments are currently listed for Pulmonary alveolar microlithiasis.
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Specialists
View all specialists →No specialists are currently listed for Pulmonary alveolar microlithiasis.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Pulmonary alveolar microlithiasis.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.How advanced is my lung disease right now, and how quickly do you expect it to progress?,Should my family members be tested for the SLC34A2 gene mutation?,What lung function tests will I need, and how often should I have them?,Are there any clinical trials or experimental treatments I might be eligible for?,At what point should we start discussing lung transplantation as an option?,What vaccinations and lifestyle changes can help protect my lungs?,Are there any specialists or centers with specific experience in treating PAM that you would recommend?
Common questions about Pulmonary alveolar microlithiasis
What is Pulmonary alveolar microlithiasis?
Pulmonary alveolar microlithiasis (PAM) is a rare lung disease where tiny calcium-containing stones, called microliths, slowly build up inside the air sacs (alveoli) of the lungs. These deposits are so small they can only be seen under a microscope, but over time they can fill the lungs and make it harder to breathe. The disease is also sometimes called microlithiasis alveolaris pulmonum. PAM is caused by changes (mutations) in the SLC34A2 gene, which normally helps control phosphate levels in the lungs. When this gene does not work properly, phosphate builds up and forms calcium-phosphate cry
How is Pulmonary alveolar microlithiasis inherited?
Pulmonary alveolar microlithiasis follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.