For decades, unexplained lung scarring was lumped into a single "idiopathic" bucket. That's changing fast. Advances in genetic research have revealed that a meaningful subset of interstitial lung disease (ILD) cases are actually familial — driven by inherited variants in telomere biology, surfactant, and MUC5B genes. Family history is now considered the strongest risk factor for ILD, with studies showing 20–25% of idiopathic pulmonary fibrosis (IPF) patients have a family history, and 31% of relatives of affected individuals also carry ILD.

Despite this progress, widespread genetic screening isn't recommended yet. High-resolution CT remains the go-to for early IPF detection, and genetic testing is reserved for targeted scenarios. Experts emphasize that a negative genetic panel doesn't rule out familial predisposition, and a positive result doesn't guarantee disease — making genetic counseling an essential companion to testing.

Key Takeaways:

• Genetic testing is most warranted in patients with ≥2 affected relatives, onset before age 50, rapid progression, or poor treatment response
• Telomere shortening below the 10th percentile for age strengthens the case for genetic workup
• Positive findings influenced clinical management in >50% of cases in a targeted Mayo Clinic study
• No genotype-specific therapies exist yet, but results can shape monitoring, treatment timing, and transplant evaluation

Why it matters: As genetic tools grow more sophisticated, pulmonologists and geneticists are moving closer to precision medicine for ILD — but experts caution the field is "promising, not yet fully mature." For now, accurate family history and multidisciplinary collaboration remain the cornerstones of care.