PURPOSE:Hermansky-Pudlak Syndrome (HPS) is a rare disorder that involves oculocutaneous albinism, platelet storage pool deficiency, interstitial lung disease, and inflammatory bowel disease. There are 8 genetic subtypes including HPS-1, common in Puerto Rico and among ethnic Puerto Ricans living in the continental U.S. Many physicians remain unaware that HPS-1 (and HPS-4) patients are at very high risk to develop interstitial lung disease (ILD) as adults.
METHODS:Since 1993, the National Human Genome Research Institute has followed HPS patients, who are seen biannually as inpatients and receive pulmonary and radiologic evaluations.
RESULTS:From 1993–2008, 298 patients were studied; 192 were genotyped Type 1 or Type 4. Pulmonary function testing and/or high resolution CT detected ILD in both types 1 and 4. The youngest ILD patient was 19, the oldest, 73. The majority developed ILD between 35 and 55 years. The youngest death was at age 27. There are three survivors identified past age 65, all with moderate ILD. No patient with HPS types 3, 5, or 6 has developed ILD.
CONCLUSION:From the first 15 years of this study, it appears all HPS type 1 and type 4 patients will eventually develop ILD. ILD begins after puberty and peaks in the 4th decade of life, and is the major cause of death for these patients. Other HPS types are not at increased risk for ILD.
CLINICAL IMPLICATIONS:HPS is a major cause of ILD in Puerto Rico and among individuals with albinism. Recognition and genotyping HPS patients will allow early monitoring and early detection of ILD. It should be possible to treat the ILD of HPS earlier than ILD due to other causes. Physicians should become familiar with HPS and evaluate patients with albinism for this disorder. Health care providers should suspect HPS especially, but not exclusively, in patients with Puerto Rican ancestry. Pulmonary function testing should begin after puberty and patients should be followed throughout their lifespan.
DISCLOSURE:Thomas Markello, None.