Progressive hemifacial atrophy

What is Progressive hemifacial atrophy?

Progressive hemifacial atrophy (PHA) is a rare acquired disorder, characterized by unilateral slowly progressive atrophy of the skin and soft tissues of half of the face leading to a sunken appearance. Muscles, cartilage and the underlying bony structures may also be involved.

Other condition names

  • Hemifacial atrophy
  • PHA
  • Parry-Romberg syndrome
  • Progressive facial hemiatrophy
  • Romberg syndrome

Inheritance type

Not applicable


  • United States: 1-9 in 1,000 000

Age of Onset

  • Adolescent
  • Adult
  • Childhood
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