| OPCA | olivopontocerebellar atrophy |
|---|---|
| PMA | index of prevalence and severity of gingivitis, where P = papillary gingiva, M = marginal gingiva, a... |
| POA | pancreatic oncofetal antigen; phalangeal osteoarthritis; preoptic area; primary optic atrophy |
| PPCRA | pigmented paravenous chorioretinal atrophy |
| PPMA | progressive postmyelitis muscular atrophy |