Oculopharyngeal muscular dystrophy (OPMD) is one of the 43 conditions covered by the MDA services program. It is characterized by droopy eyelids (ptosis), difficulty swallowing (dysphagia), and weakness of arms and legs. Generally rare, OPMD is so common among some Hispanic New Mexican families, the symptoms are often considered a "family trait" and not recognized as a healthcare issue.

Generally an inherited condition, symptoms most often begin in the mid-40s or 50s. OPMD does not appear to shorten life but can dramatically change the way people live. Although there is currently no cure for OPMD, it is important for families and their physicians to realize these "family traits" are symptoms of a disease for which there are treatment options.

The OPMD cluster among Hispanics in New Mexico is likely the largest cluster of OPMD in the United States and one of the largest in the world. The majority of patients in New Mexico were born in the Rio Grande river basin in Northern New Mexico. Researchers have not identified the source of the OPMD cluster. The disease may have been brought into New Mexico by Spanish colonists in the 16th century or by French-Canadian fur trappers in the 19th century. The cluster could also have been the result of a spontaneous mutation.

This cluster was identified through the efforts of a group of medical professionals from UNM Health Sciences Center and the New Mexico VA Health Care System. After discovering their common interest in OPMD, they combined their findings, attracted additional expertise and in November 2001, published their findings in the Journal of the American Medical Association (JAMA).