All articles starting with P
28,818 articles
Primary cutaneous plasmacytosis
Primary cutaneous plasmacytosis (ORPHA:451602) is a rare benign skin disease with mature polyclonal plasma cell infiltrates, red-brown truncal plaques, hypergammaglobulinemia, and lymphadenopathy, mainly in Japanese patients.
Primary cytoreductive surgery
Primary cytoreductive surgery, also called primary debulking surgery, is the first treatment for advanced ovarian cancer, removing as much visible tumor as possible before chemotherapy.
Primary debulking surgery
Primary debulking surgery (PDS) is the initial operation for advanced ovarian cancer, in which surgeons remove all visible tumor, typically removing the ovaries, uterus, and omentum.
Primary decomposition
Primary decomposition represents an ideal of a commutative ring as an intersection of primary ideals, generalizing prime factorization of integers; it was proved for Noetherian rings by Emmy Noether.
Primary dystonia
Primary dystonia, now termed isolated dystonia, is dystonia as the sole motor sign without brain lesion or exogenous cause; largely genetic (TOR1A/DYT1 ~30% penetrance), treated with botulinum toxin and pallidal DBS.
Primary dystonia, DYT13 type
Primary dystonia, DYT13 type (DYT13, OMIM 607671) is a rare autosomal dominant primary torsion dystonia mapped to chromosome 1p36.13–36.32 in an Italian family, with cranial-cervical or upper limb onset, mean onset age 16, mild course, gene unknown.
Primary dystonia, DYT2 type
Primary dystonia, DYT2 type (torsion dystonia 2, DYT-HPCA) is a rare autosomal recessive, childhood-onset isolated dystonia starting in distal limbs and spreading to craniocervical regions, linked to HPCA mutations but genetically unconfirmed, OMIM 224500.
Primary dystonia, DYT21 type
Primary dystonia, DYT21 type (DYT21, dystonia 21) is a rare autosomal dominant adult-onset pure torsion dystonia mapped to 2q14.3-q21.3, described in one Swedish family; gene unknown, penetrance about 75-90%.
Primary dystonia, DYT4 type
Primary dystonia, DYT4 type (DYT-TUBB4A, whispering dysphonia): rare autosomal dominant dystonia from TUBB4A mutations, marked by laryngeal dystonia, hobby horse gait, first described in an Australian family in 1985.
Primary dystonia, DYT6 type
Primary dystonia, DYT6 type (DYT6 dystonia, THAP1 dystonia) is an autosomal dominant isolated dystonia caused by THAP1 mutations, with onset averaging around 18 years, prominent cranial and cervical involvement, dysphonia, and reduced penetrance near 60%.
Primary education
Primary education (elementary education, ISCED level 1) is the first formal schooling stage, ages roughly 5 to 11, teaching literacy, numeracy and social skills; free and compulsory under UDHR article 26, with 85% global completion and 79 million primary-age children out of school in 2024.
Primary education in England
Primary education in England is the first stage of public schooling for children aged 4 to 11, organized as Key Stages 1 and 2 under the National Curriculum.
Primary education in Northern Ireland
Primary education in Northern Ireland is the seven-year, publicly funded schooling from age 4 or 5 to age 11, divided into controlled, Catholic maintained, Irish-medium, and integrated sectors.
Primary effusion lymphoma
Primary effusion lymphoma (PEL), or body cavity-based lymphoma, is a rare aggressive HHV-8-positive B-cell non-Hodgkin lymphoma causing malignant pleural, peritoneal, or pericardial effusions without tumor masses, mainly in immunocompromised HIV patients, often coinfected with EBV.
Primary election
Primary election: US intra-party election choosing nominees for the general election; types include open, closed, semi-closed, top-two, and nonpartisan; first statewide primary 1899 Minnesota, first presidential primary 1901 Florida; turnout far below general elections.
Primary endpoint
A primary endpoint is the main outcome of a clinical trial, chosen in advance, on which its hypothesis is tested and regulatory approval is judged.
Primary erythromelalgia
Primary erythromelalgia (primary erythermalgia, Weir Mitchell disease) is a rare autosomal dominant neuropathy of burning, red, hot extremities caused by gain-of-function SCN9A mutations affecting the Nav1.7 sodium channel, with childhood onset and relief by cooling.
Primary essential cutis verticis gyrata
Primary essential cutis verticis gyrata (CVG), ORPHA:357220, a rare benign scalp disorder with cerebriform folds in otherwise healthy people, mainly males, onset after puberty, treated by hygiene or surgical excision.
Primary failure of tooth eruption
Primary failure of tooth eruption (PFE), or primary retention of teeth, a rare autosomal dominant disorder (OMIM 125350) in which non-ankylosed posterior teeth fail to erupt without obstruction, linked to PTH1R mutations and resistant to orthodontic force.
Primary familial and congenital erythrocytosis
Primary familial and congenital erythrocytosis (PFCE, ECYT1, primary familial congenital polycythemia) is an autosomal dominant EPOR-gene disorder causing EPO-independent red cell excess, first described in skier Eero Mäntyranta.
Primary Fanconi renotubular syndrome
Primary Fanconi renotubular syndrome (DeToni-Debré-Fanconi syndrome, ORPHA:3337) is a rare genetic proximal tubule disorder causing urinary loss of glucose, amino acids, phosphate, and bicarbonate; genes GATM, EHHADH, SLC34A1; distinct from Fanconi anemia.
Primary fatty amines
Primary fatty amines are organic compounds with a long fatty alkyl chain attached to ammonia, derived from natural fats and oils and produced at over 1 million tons per year.
Primary female infertility
Primary female infertility (ICD-11 GA31.0) is the failure of a woman ever to achieve pregnancy after 12 months of regular unprotected intercourse. Causes include tubal, uterine, ovarian, and endocrine disorders; WHO issued its first infertility guideline in 2025.
Primary frequency response
Primary frequency response is the rapid, automatic action of grid generators to arrest and stabilize frequency deviations within seconds, until secondary control restores normal frequency.
Primary gout
Primary gout is gout occurring without an identified acquired cause of high blood urate, such as another disorder or urate-raising drugs; it has risen most in older men.
Primary health care
Primary health care (PHC) is WHO's whole-of-society approach to health, first defined at Alma-Ata (1978) and renewed at Astana (2018), spanning primary care, multisectoral action, and empowered communities as the foundation for universal health coverage.
Primary hepatic neuroendocrine carcinoma
Primary hepatic neuroendocrine carcinoma (PHNEC) is a rare malignant liver tumor made of neuroendocrine cells that arises in the liver rather than spreading from another organ, first reported in 1958.
Primary hypercholesterolaemia
Primary hypercholesterolaemia (ICD-11 5C80.00): genetically driven high cholesterol, including familial hypercholesterolaemia (LDLR, APOB, PCSK9) and polygenic forms, distinguished from secondary causes and treated with statins.
Primary hypereosinophilic syndrome
Primary hypereosinophilic syndrome (neoplastic HES, HES-N, ORPHA:314950, ICD-10 D47.5): clonal, neoplastic stem cell-derived eosinophils causing hypereosinophilia ≥1.5×10^9/L for ≥6 months with organ damage, no secondary cause; treated with TKIs or steroids.
Primary hyperoxaluria
Primary hyperoxaluria (PH1, PH2, PH3; AGXT, GRHPR, HOGA1) is a rare autosomal recessive liver enzyme disorder causing oxalate overproduction, recurrent calcium oxalate stones, kidney failure, and systemic oxalosis; treated with pyridoxine, RNAi drugs lumasiran and nedosiran, and transplantation.