🏷

Classifications

Harrison's Chapter

👪

Inheritance

1

Autosomal Dominant

PRKAR1A-related PPNAD, whether isolated or in the context of Carney complex, is inherited in an autosomal dominant manner. PRKAR1A behaves as a tumor suppressor, with inactivating germline variants and frequently a somatic second hit at the tissue level. Some cases arise de novo, and PRKACA copy-number gain has been reported as a de novo (non-heritable) event.

Show evidence (2 references)

PMID:20548949 SUPPORT Model Organism

"Inactivating mutations in PRKAR1A, a gene encoding the type 1 alpha-regulatory subunit (R1alpha) of the cAMP-dependent protein kinase (PKA) have been found in 80% of CNC patients with Cushing's syndrome."

Establishes PRKAR1A inactivating mutations as the predominant cause of Carney complex with Cushing syndrome, the autosomal dominant PPNAD setting. The cited publication is a Prkar1a knockout mouse study; this snippet quotes its summary of prior human clinical findings.

PMID:37988664 SUPPORT Human Clinical

"a rise in the copy number of the duplication-containing PRKACA gene on chromosome 19p13.13p13.12, a de novo but not heritable gene defect that causes disease."

Documents a de novo, non-heritable PRKACA copy-number gain as a cause of PPNAD, illustrating that not all cases are inherited.

◆

Subtypes

4

PPNAD1 (PRKAR1A)

PRKAR1A hgnc:9388 {'name': 'Autosomal Dominant'}

PPNAD caused by inactivating variants in PRKAR1A, the most common cause and the gene associated with Carney complex type 1. PRKAR1A was the most frequent pathogenic variant in tested PPNAD patients, and PRKAR1A variants correlate with spotty skin pigmentation in Carney-complex-associated PPNAD.

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"The most common mutation was PKAR1A, accounting for 79.47% (120/151)."

Establishes PRKAR1A as the most common pathogenic gene among tested PPNAD patients.

PPNAD2 (PDE11A)

PDE11A hgnc:8773

PPNAD associated with variants in PDE11A, a dual cAMP/cGMP phosphodiesterase. Reduced phosphodiesterase activity decreases cAMP degradation, increasing cAMP/PKA signaling. PDE11A variants frequently co-occurred with PRKAR1A in the pooled cohort.

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients."

Lists PDE11A among the genes detected in PPNAD patients.

PPNAD3 (PDE8B)

PDE8B hgnc:8794

PPNAD associated with variants in PDE8B, a high-affinity cAMP-specific phosphodiesterase. As with PDE11A, reduced cAMP degradation enhances cAMP/PKA signaling in adrenocortical cells.

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients."

Lists PDE8B among the genes detected in PPNAD patients.

PPNAD4 (PRKACA)

PRKACA hgnc:9380

PPNAD associated with copy-number gain (amplification) of PRKACA, the PKA catalytic subunit alpha. Increased PRKACA dosage directly increases PKA catalytic activity. A germline PRKACA copy-number gain on chromosome 19p13.13p13.12 was reported as a de novo cause of pediatric PPNAD.

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"a case of a female Chinese patient with PPNAD caused by the germline PRKACA gene copy number gain of chromosome 19."

Documents PRKACA copy-number gain as a cause of PPNAD.

⚙

Pathophysiology

5

PRKAR1A Loss and Constitutive PKA Activation

Germline inactivating variants in PRKAR1A reduce or eliminate the type I alpha regulatory subunit (RIalpha) of protein kinase A. Loss of regulatory restraint releases the PKA catalytic subunits, producing increased cAMP-stimulated catalytic kinase activity in adrenocortical cells. Many PRKAR1A variants are premature stop codons triggering nonsense-mediated decay and haploinsufficiency, with up-regulation of other PKA subunits.

adrenocortical cell CL:0002097

cAMP/PKA signal transduction GO:0141156 ↑ INCREASED activation of protein kinase A activity GO:0034199 ↑ INCREASED

Downstream

Autonomous Steroidogenesis and Adrenocortical Hyperplasia

MAPK Pathway Activation and Proliferation

Show evidence (2 references)

PMID:16569736 SUPPORT In Vitro

"Increased cAMP-stimulated total kinase activity was associated with mt-PRKAR1A."

Demonstrates that PRKAR1A mutation increases cAMP-stimulated PKA activity in adrenocortical tissue.

PMID:16569736 SUPPORT In Vitro

"mt-PRKAR1A causes increased total cAMP-stimulated kinase activity, likely the result of up-regulation of other PKA subunits caused by down-regulation of RIalpha"

Mechanistically links RIalpha down-regulation to compensatory PKA subunit up-regulation and increased kinase activity.

Autonomous Steroidogenesis and Adrenocortical Hyperplasia

Constitutive PKA activity drives autonomous, ACTH-independent expression of steroidogenic genes and cortisol production, together with deregulated adrenocortical cell differentiation and increased proliferation, yielding bilateral micronodular hyperplasia. The adrenal-cortex-specific Prkar1a knockout mouse recapitulates pituitary-independent Cushing syndrome and bilateral hyperplasia, demonstrating that RIalpha loss is sufficient. Transcriptomic studies show increased expression of steroidogenic acute regulatory protein and the steroidogenic enzymes CYP17A1 and CYP21A2.

adrenocortical cell CL:0002097

glucocorticoid biosynthetic process GO:0006704 ↑ INCREASED cell population proliferation GO:0008283 ↑ INCREASED

Downstream

mTORC1 Activation and Apoptosis Resistance

Show evidence (3 references)

PMID:20548949 SUPPORT Model Organism

"AdKO mice develop pituitary-independent Cushing's syndrome with increased PKA activity. This leads to autonomous steroidogenic genes expression and deregulated adreno-cortical cells differentiation, increased proliferation and resistance to apoptosis."

In vivo evidence that PKA activation produces autonomous steroidogenesis, deregulated differentiation, proliferation, and apoptosis resistance.

PMID:20548949 SUPPORT Model Organism

"loss of R1alpha is sufficient to induce autonomous adrenal hyper-activity and bilateral hyperplasia, both observed in human PPNAD."

Establishes that RIalpha loss is sufficient to cause the autonomous hyperactivity and bilateral hyperplasia of human PPNAD.

PMID:16278264 SUPPORT Human Clinical

"Examples of well-characterized genes expressed at significantly higher levels in PPNAD included steroidogenic acute regulator, chromogranin A, and those coding for the steroidogenic enzymes P450 cytochromes CYP17A1 and CYP21A2."

Transcriptomic profiling confirms up-regulation of steroidogenic machinery in PPNAD adrenal tissue.

mTORC1 Activation and Apoptosis Resistance

PKA activates the mTOR pathway in adrenocortical cells, and this contributes in vivo to resistance to apoptosis in PPNAD, allowing accumulation of autonomously functioning nodular cells. Pharmacologic mTORC1 inhibition with rapamycin restored apoptosis sensitivity in the Prkar1a knockout mouse model, nominating mTORC1 as a candidate therapeutic target.

adrenocortical cell CL:0002097

TOR signaling GO:0031929 ↑ INCREASED negative regulation of apoptotic process GO:0043066 ↑ INCREASED

Show evidence (1 reference)

PMID:24865460 SUPPORT Model Organism

"mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD)"

Directly establishes the PKA to mTOR to apoptosis-resistance axis in PPNAD.

MAPK Pathway Activation and Proliferation

PRKAR1A-mutant adrenocortical tissue shows enhanced MAPK signaling, with increased phosphorylated ERK1/2, B-raf, phospho-MEK1/2, and phospho-c-Myc. These changes are proposed to provide proliferative signals contributing to nodule formation. Comparative whole-genome expression profiling further shows overexpression of Wnt pathway genes (CCND1, CTNNB1, LEF1, LRP5, WISP1, WNT3) in PRKAR1A-mutant lesions, linking cAMP/PKA activation to Wnt-driven proliferative programs.

adrenocortical cell CL:0002097

MAPK cascade GO:0000165 ↑ INCREASED Wnt signaling pathway GO:0016055 ↑ INCREASED

Show evidence (2 references)

PMID:16569736 SUPPORT In Vitro

"These changes, associated with enhanced MAPK activity, may be, in part, responsible for the proliferative signals that result in primary pigmented nodular adrenocortical disease."

Links enhanced MAPK activity downstream of PRKAR1A mutation to the proliferation underlying PPNAD.

PMID:22259056 SUPPORT Human Clinical

"Genes related to the Wnt signaling pathway (CCND1, CTNNB1, LEF1, LRP5, WISP1, and WNT3) were overexpressed in PRKAR1A-mutant lesions."

Demonstrates Wnt pathway gene overexpression specifically in PRKAR1A-mutant PPNAD lesions.

c-KIT/SCF Oncogenic Axis

In PRKAR1A-mutant adrenal cortex, the c-KIT proto-oncogene and its ligand stem cell factor (SCF) become expressed within nodular areas, an expression dependent on PRKAR1A status and PKA activity. KIT inhibition with imatinib reduced viability, caused growth arrest, and induced apoptosis in PRKAR1A-deficient adrenocortical cells and inhibited tumor growth in xenografts, suggesting c-KIT inhibition as a potential alternative therapy.

adrenocortical cell CL:0002097

Show evidence (2 references)

PMID:32738126 SUPPORT In Vitro

"c-KIT is expressed in PPNAD, an expression that appears to be dependent on PRKAR1A and/or PKA activity."

Establishes PRKAR1A/PKA-dependent c-KIT expression in PPNAD.

PMID:32738126 SUPPORT In Vitro

"Treatment of the CAR47 cells with IM resulted in reduced cell viability, growth arrest, and apoptosis."

Shows that KIT inhibition with imatinib reduces growth and induces apoptosis in PRKAR1A-deficient cells.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

10

Cardiovascular 1

Hypertension Hypertension HP:0000822

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"the patient had diabetes, mild hypertension, low bone mass, a low ACTH level, and hypercortisolemia"

Case report documents hypertension in a PPNAD patient.

Endocrine 1

Diabetes mellitus Diabetes mellitus HP:0000819

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"it was discovered that the patient had diabetes, mild hypertension, low bone mass, a low ACTH level, and hypercortisolemia"

Case report documents diabetes in a PPNAD patient.

Musculoskeletal 1

Osteoporosis/Osteopenia VERY_FREQUENT Osteopenia HP:0000938

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"94.29% were combined with osteoporosis/osteopenia."

Establishes osteoporosis/osteopenia as a very frequent feature of PPNAD, present in 94.29% of the pooled cohort, supporting the VERY_FREQUENT (80-99%) frequency band.

Growth 2

Weight gain Increased body weight HP:0004324

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"The patient initially presented with kidney stones, short stature, and obesity."

Case report documents obesity at presentation in a PPNAD patient.

Short stature Short stature HP:0004322

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"Pediatric patients with PPNAD typically have unusual skin lesions and slow growth with unknown causes."

Documents slow growth/short stature as typical in pediatric PPNAD.

Other 5

ACTH-independent Cushing syndrome Primary hypercortisolism HP:0001579

Show evidence (1 reference)

PMID:20548949 SUPPORT Model Organism

"primary pigmented nodular adrenocortical disease (PPNAD), a bilateral adrenocortical hyperplasia causing pituitary-independent Cushing's syndrome."

Defines PPNAD as causing pituitary-independent (ACTH-independent) Cushing syndrome.

Increased circulating cortisol Increased circulating cortisol level HP:0003118

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"the patient had diabetes, mild hypertension, low bone mass, a low ACTH level, and hypercortisolemia"

Case report documents hypercortisolemia in PPNAD.

Decreased circulating ACTH Decreased circulating ACTH concentration HP:0002920

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"the patient had diabetes, mild hypertension, low bone mass, a low ACTH level, and hypercortisolemia"

Case report documents a low ACTH level consistent with ACTH-independent disease.

Pigmented micronodular adrenocortical disease Pigmented micronodular adrenocortical disease HP:0001580

Show evidence (2 references)

PMID:34680514 SUPPORT Human Clinical

"Micronodular adrenal hyperplasia, including the primary pigmented micronodular adrenal dysplasia (PPNAD) and the isolated micronodular adrenal hyperplasia (iMAD), can be distinguished from the primary bilateral macronodular adrenal hyperplasia (PBMAH) according to the size of the nodules."

Describes PPNAD as a micronodular form of bilateral adrenal hyperplasia, defined by its small (micronodular) cortical nodules in contrast to macronodular hyperplasia.

PMID:16278264 SUPPORT Human Clinical

"primary pigmented nodular adrenocortical disease (PPNAD) tissue from two adolescent female patients"

Confirms PPNAD adrenal pathology in patient tissue studied.

Spotty skin pigmentation (Carney complex) Multiple lentigines HP:0001003

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"There was a significant correlation between PRKAR1A pathogenic variant and spotty skin pigmentation in CNC concurrent with PPNAD (p < 0.05)."

Documents spotty skin pigmentation as a Carney-complex feature correlated with PRKAR1A variants in PPNAD.

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Genetic Associations

4

PRKAR1A (Germline Inactivating Variants)

Gene: PRKAR1A hgnc:9388

Autosomal Dominant

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"The most common mutation was PKAR1A, accounting for 79.47% (120/151)."

Confirms PRKAR1A as the most frequently identified gene in tested PPNAD patients.

PDE11A (Reduced-Function Variants)

Gene: PDE11A hgnc:8773

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients."

Lists PDE11A among the pathogenic genes detected in PPNAD patients.

PDE8B (Reduced-Function Variants)

Gene: PDE8B hgnc:8794

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients."

Lists PDE8B among the pathogenic genes detected in PPNAD patients.

PRKACA (Copy-Number Gain)

Gene: PRKACA hgnc:9380 variant_origin: GERMLINE

Show evidence (1 reference)

PMID:37988664 SUPPORT Human Clinical

"a rise in the copy number of the duplication-containing PRKACA gene on chromosome 19p13.13p13.12, a de novo but not heritable gene defect that causes disease."

Documents germline PRKACA copy-number gain as a de novo cause of PPNAD.

💊

Medical Actions

6

Bilateral Adrenalectomy

Action: adrenalectomy MAXO:0001030

Bilateral adrenalectomy has historically been the definitive treatment for hypercortisolism in PPNAD, achieving cure of cortisol excess but requiring lifelong glucocorticoid and mineralocorticoid replacement. More recent practice increasingly favors unilateral or subtotal resection to avoid permanent adrenal insufficiency.

Show evidence (1 reference)

PMID:34680514 PARTIAL Human Clinical

"the treatment of bilateral adrenal hyperplasia will be discussed, focusing on current data on unilateral adrenalectomy."

Review of treatment for bilateral adrenal hyperplasia including PPNAD; surgical resection is the mainstay, with current data increasingly favoring unilateral over bilateral adrenalectomy. This snippet supports adrenalectomy as the treatment modality but not bilateral resection as the preferred contemporary approach.

Unilateral Adrenalectomy

Action: adrenalectomy MAXO:0001030

Unilateral adrenalectomy may be considered in selected patients, including women with fertility needs, although some cases require completion adrenalectomy if hypercortisolism persists or recurs.

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Unilateral adrenal resection may be considered as an option for women with fertility needs."

Supports unilateral adrenalectomy as an option for fertility preservation.

Steroidogenesis Inhibitor Pharmacotherapy

Action: Pharmacotherapy NCIT:C15986

Agent: ketoconazole CHEBI:47519 metyrapone CHEBI:44241 mitotane CHEBI:6954

Steroidogenesis inhibitors such as ketoconazole, metyrapone, and mitotane are used to control hypercortisolism as a bridge to surgery or in persistent or recurrent disease.

Show evidence (1 reference)

PMID:34680514 PARTIAL Human Clinical

"the treatment of bilateral adrenal hyperplasia will be discussed, focusing on current data on unilateral adrenalectomy."

This review covers the treatment of bilateral adrenal hyperplasia including PPNAD. The cited snippet establishes that the review addresses PPNAD treatment but focuses on adrenalectomy rather than pharmacotherapy; steroidogenesis inhibitors are standard pharmacologic options for hypercortisolism but are not specifically named in this snippet, so the support is indirect.

Genetic Counseling

Action: Genetic Counseling NCIT:C15240

Genetic counseling and cascade testing are recommended for families with PRKAR1A-related disease, together with surveillance for Carney complex manifestations such as cardiac myxoma.

Show evidence (1 reference)

PMID:39006359 SUPPORT Human Clinical

"Patients with PPNAD with spotty skin pigmentation should consider the PRKAR1A pathogenic variant and pay attention to CNC."

Supports genetic evaluation and Carney complex surveillance in PPNAD with spotty skin pigmentation.

Experimental mTORC1 Inhibition

Action: Pharmacotherapy NCIT:C15986

Agent: sirolimus CHEBI:9168

mTORC1 inhibition with rapamycin restored apoptosis sensitivity in the Prkar1a knockout mouse model, nominating mTORC1 as a candidate therapeutic target; this is an experimental, mechanism-informed direction rather than standard care.

Show evidence (1 reference)

PMID:24865460 SUPPORT Model Organism

"mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD)"

Provides the in vivo rationale for mTORC1 inhibition as an experimental therapy in PPNAD.

Experimental KIT Inhibition

Action: Pharmacotherapy NCIT:C15986

Agent: imatinib CHEBI:45783

KIT inhibition with imatinib reduced viability and induced apoptosis in PRKAR1A-deficient adrenocortical cells and inhibited xenograft growth, suggesting c-KIT inhibitors as a possible alternative therapy when other treatments are not optimal; this remains experimental.

Show evidence (1 reference)

PMID:32738126 SUPPORT In Vitro

"c-KIT inhibition decreased growth, suggesting that c-KIT inhibitors may be a reasonable alternative therapy to be tested in PPNAD, when other treatments are not optimal."

Provides the experimental rationale for KIT inhibition as an alternative therapy in PPNAD.

🔬

Clinical Trials

1

NCT00001452 RECRUITING

NIH observational study defining the genotype and clinical phenotype of PPNAD, Carney complex, and related conditions, including genetic basis, molecular tumor changes, carrier identification, and prognosis.

Show evidence (1 reference)

clinicaltrials:NCT00001452 SUPPORT

"Primary pigmented nodular adrenocortical disease (PPNAD) is a pituitary-independent, primary adrenal form of hypercortisolism"

The trial summary characterizes PPNAD as pituitary-independent primary adrenal hypercortisolism, the disease under study.

{ }

Source YAML

click to show

name: Primary Pigmented Nodular Adrenocortical Disease
creation_date: "2026-06-05T12:00:00Z"
category: Mendelian
description: >-
  Primary pigmented nodular adrenocortical disease (PPNAD) is a rare,
  typically bilateral micronodular form of adrenocortical hyperplasia that
  produces cortisol autonomously, causing ACTH-independent (pituitary-independent)
  Cushing syndrome that often presents in childhood or young adulthood and may
  be cyclical or subclinical. It occurs as an isolated condition or, in roughly
  one-third of cases, as the most frequent endocrine manifestation of Carney
  complex. The dominant disease mechanism is dysregulated cAMP/PKA signaling,
  most often caused by germline inactivating variants in PRKAR1A (the type I
  alpha regulatory subunit of protein kinase A); additional causes affect cAMP
  phosphodiesterases (PDE11A, PDE8B) or the PKA catalytic subunit (PRKACA copy
  number gain). Loss of PKA regulatory restraint drives constitutive PKA
  catalytic activity, autonomous steroidogenesis, abnormal adrenocortical
  differentiation, increased proliferation, and resistance to apoptosis, with
  downstream involvement of mTORC1 and Wnt signaling programs. Histologically
  the adrenal glands are small to normal in size and contain multiple small
  pigmented cortical nodules with internodular cortical atrophy.
synonyms:
- PPNAD
- isolated PPNAD
- familial isolated PPNAD
- micronodular adrenal disease
- primary pigmented nodular adrenal dysplasia
- pigmented nodular adrenocortical disease
parents:
- Endocrine Disorders
- Adrenal Gland Diseases
disease_term:
  preferred_term: Primary Pigmented Nodular Adrenocortical Disease
  term:
    id: MONDO:0015999
    label: primary pigmented nodular adrenocortical disease
inheritance:
- name: Autosomal Dominant
  description: >-
    PRKAR1A-related PPNAD, whether isolated or in the context of Carney complex,
    is inherited in an autosomal dominant manner. PRKAR1A behaves as a tumor
    suppressor, with inactivating germline variants and frequently a somatic
    second hit at the tissue level. Some cases arise de novo, and PRKACA
    copy-number gain has been reported as a de novo (non-heritable) event.
  evidence:
  - reference: PMID:20548949
    reference_title: "Cushing's syndrome and fetal features resurgence in adrenal cortex-specific Prkar1a knockout mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Inactivating mutations in PRKAR1A, a gene encoding the type 1
      alpha-regulatory subunit (R1alpha) of the cAMP-dependent protein kinase
      (PKA) have been found in 80% of CNC patients with Cushing's syndrome.
    explanation: >-
      Establishes PRKAR1A inactivating mutations as the predominant cause of
      Carney complex with Cushing syndrome, the autosomal dominant PPNAD setting.
      The cited publication is a Prkar1a knockout mouse study; this snippet
      quotes its summary of prior human clinical findings.
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a rise in the copy number of the duplication-containing PRKACA gene on
      chromosome 19p13.13p13.12, a de novo but not heritable gene defect that
      causes disease.
    explanation: >-
      Documents a de novo, non-heritable PRKACA copy-number gain as a cause of
      PPNAD, illustrating that not all cases are inherited.
prevalence:
- population: Patients with Cushing syndrome
  prevalence_class: UNKNOWN
  percentage: Unknown
  notes: >-
    PPNAD is a rare cause of endogenous Cushing syndrome that is frequently
    misdiagnosed; precise population prevalence and incidence estimates have not
    been established. A pooled systematic review compiled 210 reported patients
    from 86 articles, with a median age of 22 years and a female-to-male ratio
    of 2:1.
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A total of 210 patients in 86 articles were enrolled with a median age of
      22 and a female-to-male ratio of 2:1.
    explanation: >-
      Provides the cohort size, median age, and sex ratio from the largest
      pooled synthesis of reported PPNAD cases.
pathophysiology:
- name: PRKAR1A Loss and Constitutive PKA Activation
  description: >-
    Germline inactivating variants in PRKAR1A reduce or eliminate the type I
    alpha regulatory subunit (RIalpha) of protein kinase A. Loss of regulatory
    restraint releases the PKA catalytic subunits, producing increased
    cAMP-stimulated catalytic kinase activity in adrenocortical cells. Many
    PRKAR1A variants are premature stop codons triggering nonsense-mediated
    decay and haploinsufficiency, with up-regulation of other PKA subunits.
  cell_types:
  - preferred_term: adrenocortical cell
    term:
      id: CL:0002097
      label: cortical cell of adrenal gland
  biological_processes:
  - preferred_term: cAMP/PKA signal transduction
    term:
      id: GO:0141156
      label: cAMP/PKA signal transduction
    modifier: INCREASED
  - preferred_term: activation of protein kinase A activity
    term:
      id: GO:0034199
      label: activation of protein kinase A activity
    modifier: INCREASED
  evidence:
  - reference: PMID:16569736
    reference_title: "PRKAR1A Mutations and protein kinase A interactions with other signaling pathways in the adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Increased cAMP-stimulated total kinase activity was associated with
      mt-PRKAR1A.
    explanation: >-
      Demonstrates that PRKAR1A mutation increases cAMP-stimulated PKA activity
      in adrenocortical tissue.
  - reference: PMID:16569736
    reference_title: "PRKAR1A Mutations and protein kinase A interactions with other signaling pathways in the adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      mt-PRKAR1A causes increased total cAMP-stimulated kinase activity, likely
      the result of up-regulation of other PKA subunits caused by
      down-regulation of RIalpha
    explanation: >-
      Mechanistically links RIalpha down-regulation to compensatory PKA subunit
      up-regulation and increased kinase activity.
  downstream:
  - target: Autonomous Steroidogenesis and Adrenocortical Hyperplasia
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:20548949
      reference_title: "Cushing's syndrome and fetal features resurgence in adrenal cortex-specific Prkar1a knockout mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        AdKO mice develop pituitary-independent Cushing's syndrome with increased
        PKA activity. This leads to autonomous steroidogenic genes expression and
        deregulated adreno-cortical cells differentiation, increased proliferation
        and resistance to apoptosis.
      explanation: >-
        Links increased PKA activity directly to autonomous steroidogenesis and
        adrenocortical hyperplasia.
  - target: MAPK Pathway Activation and Proliferation
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:16569736
      reference_title: "PRKAR1A Mutations and protein kinase A interactions with other signaling pathways in the adrenal cortex."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        These changes, associated with enhanced MAPK activity, may be, in part,
        responsible for the proliferative signals that result in primary pigmented
        nodular adrenocortical disease.
      explanation: >-
        Links PRKAR1A/PKA dysregulation to enhanced MAPK activity driving
        proliferation.
- name: Autonomous Steroidogenesis and Adrenocortical Hyperplasia
  description: >-
    Constitutive PKA activity drives autonomous, ACTH-independent expression of
    steroidogenic genes and cortisol production, together with deregulated
    adrenocortical cell differentiation and increased proliferation, yielding
    bilateral micronodular hyperplasia. The adrenal-cortex-specific Prkar1a
    knockout mouse recapitulates pituitary-independent Cushing syndrome and
    bilateral hyperplasia, demonstrating that RIalpha loss is sufficient.
    Transcriptomic studies show increased expression of steroidogenic acute
    regulatory protein and the steroidogenic enzymes CYP17A1 and CYP21A2.
  cell_types:
  - preferred_term: adrenocortical cell
    term:
      id: CL:0002097
      label: cortical cell of adrenal gland
  biological_processes:
  - preferred_term: glucocorticoid biosynthetic process
    term:
      id: GO:0006704
      label: glucocorticoid biosynthetic process
    modifier: INCREASED
  - preferred_term: cell population proliferation
    term:
      id: GO:0008283
      label: cell population proliferation
    modifier: INCREASED
  evidence:
  - reference: PMID:20548949
    reference_title: "Cushing's syndrome and fetal features resurgence in adrenal cortex-specific Prkar1a knockout mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      AdKO mice develop pituitary-independent Cushing's syndrome with increased
      PKA activity. This leads to autonomous steroidogenic genes expression and
      deregulated adreno-cortical cells differentiation, increased proliferation
      and resistance to apoptosis.
    explanation: >-
      In vivo evidence that PKA activation produces autonomous steroidogenesis,
      deregulated differentiation, proliferation, and apoptosis resistance.
  - reference: PMID:20548949
    reference_title: "Cushing's syndrome and fetal features resurgence in adrenal cortex-specific Prkar1a knockout mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      loss of R1alpha is sufficient to induce autonomous adrenal hyper-activity
      and bilateral hyperplasia, both observed in human PPNAD.
    explanation: >-
      Establishes that RIalpha loss is sufficient to cause the autonomous
      hyperactivity and bilateral hyperplasia of human PPNAD.
  - reference: PMID:16278264
    reference_title: "Serial analysis of gene expression in adrenocortical hyperplasia caused by a germline PRKAR1A mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Examples of well-characterized genes expressed at significantly higher
      levels in PPNAD included steroidogenic acute regulator, chromogranin A,
      and those coding for the steroidogenic enzymes P450 cytochromes CYP17A1
      and CYP21A2.
    explanation: >-
      Transcriptomic profiling confirms up-regulation of steroidogenic
      machinery in PPNAD adrenal tissue.
  downstream:
  - target: mTORC1 Activation and Apoptosis Resistance
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:24865460
      reference_title: "mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD)."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        mTOR pathway is activated by PKA in adrenocortical cells and participates
        in vivo to apoptosis resistance in primary pigmented nodular
        adrenocortical disease (PPNAD)
      explanation: >-
        Links PKA-driven steroidogenic adrenocortical cells to mTOR activation
        and apoptosis resistance.
- name: mTORC1 Activation and Apoptosis Resistance
  description: >-
    PKA activates the mTOR pathway in adrenocortical cells, and this contributes
    in vivo to resistance to apoptosis in PPNAD, allowing accumulation of
    autonomously functioning nodular cells. Pharmacologic mTORC1 inhibition with
    rapamycin restored apoptosis sensitivity in the Prkar1a knockout mouse
    model, nominating mTORC1 as a candidate therapeutic target.
  cell_types:
  - preferred_term: adrenocortical cell
    term:
      id: CL:0002097
      label: cortical cell of adrenal gland
  biological_processes:
  - preferred_term: TOR signaling
    term:
      id: GO:0031929
      label: TOR signaling
    modifier: INCREASED
  - preferred_term: negative regulation of apoptotic process
    term:
      id: GO:0043066
      label: negative regulation of apoptotic process
    modifier: INCREASED
  evidence:
  - reference: PMID:24865460
    reference_title: "mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD)."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      mTOR pathway is activated by PKA in adrenocortical cells and participates
      in vivo to apoptosis resistance in primary pigmented nodular
      adrenocortical disease (PPNAD)
    explanation: >-
      Directly establishes the PKA to mTOR to apoptosis-resistance axis in PPNAD.
- name: MAPK Pathway Activation and Proliferation
  description: >-
    PRKAR1A-mutant adrenocortical tissue shows enhanced MAPK signaling, with
    increased phosphorylated ERK1/2, B-raf, phospho-MEK1/2, and phospho-c-Myc.
    These changes are proposed to provide proliferative signals contributing to
    nodule formation. Comparative whole-genome expression profiling further
    shows overexpression of Wnt pathway genes (CCND1, CTNNB1, LEF1, LRP5, WISP1,
    WNT3) in PRKAR1A-mutant lesions, linking cAMP/PKA activation to Wnt-driven
    proliferative programs.
  cell_types:
  - preferred_term: adrenocortical cell
    term:
      id: CL:0002097
      label: cortical cell of adrenal gland
  biological_processes:
  - preferred_term: MAPK cascade
    term:
      id: GO:0000165
      label: MAPK cascade
    modifier: INCREASED
  - preferred_term: Wnt signaling pathway
    term:
      id: GO:0016055
      label: Wnt signaling pathway
    modifier: INCREASED
  evidence:
  - reference: PMID:16569736
    reference_title: "PRKAR1A Mutations and protein kinase A interactions with other signaling pathways in the adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      These changes, associated with enhanced MAPK activity, may be, in part,
      responsible for the proliferative signals that result in primary pigmented
      nodular adrenocortical disease.
    explanation: >-
      Links enhanced MAPK activity downstream of PRKAR1A mutation to the
      proliferation underlying PPNAD.
  - reference: PMID:22259056
    reference_title: "Activation of cyclic AMP signaling leads to different pathway alterations in lesions of the adrenal cortex caused by germline PRKAR1A defects versus those due to somatic GNAS mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Genes related to the Wnt signaling pathway (CCND1, CTNNB1, LEF1, LRP5,
      WISP1, and WNT3) were overexpressed in PRKAR1A-mutant lesions.
    explanation: >-
      Demonstrates Wnt pathway gene overexpression specifically in
      PRKAR1A-mutant PPNAD lesions.
- name: c-KIT/SCF Oncogenic Axis
  description: >-
    In PRKAR1A-mutant adrenal cortex, the c-KIT proto-oncogene and its ligand
    stem cell factor (SCF) become expressed within nodular areas, an expression
    dependent on PRKAR1A status and PKA activity. KIT inhibition with imatinib
    reduced viability, caused growth arrest, and induced apoptosis in
    PRKAR1A-deficient adrenocortical cells and inhibited tumor growth in
    xenografts, suggesting c-KIT inhibition as a potential alternative therapy.
  cell_types:
  - preferred_term: adrenocortical cell
    term:
      id: CL:0002097
      label: cortical cell of adrenal gland
  evidence:
  - reference: PMID:32738126
    reference_title: "c-KIT oncogene expression in PRKAR1A-mutant adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      c-KIT is expressed in PPNAD, an expression that appears to be dependent on
      PRKAR1A and/or PKA activity.
    explanation: >-
      Establishes PRKAR1A/PKA-dependent c-KIT expression in PPNAD.
  - reference: PMID:32738126
    reference_title: "c-KIT oncogene expression in PRKAR1A-mutant adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Treatment of the CAR47 cells with IM resulted in reduced cell viability,
      growth arrest, and apoptosis.
    explanation: >-
      Shows that KIT inhibition with imatinib reduces growth and induces
      apoptosis in PRKAR1A-deficient cells.
has_subtypes:
- name: PPNAD1
  display_name: "PPNAD1 (PRKAR1A)"
  description: >-
    PPNAD caused by inactivating variants in PRKAR1A, the most common cause and
    the gene associated with Carney complex type 1. PRKAR1A was the most frequent
    pathogenic variant in tested PPNAD patients, and PRKAR1A variants correlate
    with spotty skin pigmentation in Carney-complex-associated PPNAD.
  genes:
  - preferred_term: PRKAR1A
    term:
      id: hgnc:9388
      label: PRKAR1A
  inheritance:
  - name: Autosomal Dominant
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The most common mutation was PKAR1A, accounting for 79.47% (120/151).
    explanation: >-
      Establishes PRKAR1A as the most common pathogenic gene among tested PPNAD
      patients.
- name: PPNAD2
  display_name: "PPNAD2 (PDE11A)"
  description: >-
    PPNAD associated with variants in PDE11A, a dual cAMP/cGMP phosphodiesterase.
    Reduced phosphodiesterase activity decreases cAMP degradation, increasing
    cAMP/PKA signaling. PDE11A variants frequently co-occurred with PRKAR1A in
    the pooled cohort.
  genes:
  - preferred_term: PDE11A
    term:
      id: hgnc:8773
      label: PDE11A
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5)
      were detected in the patients.
    explanation: >-
      Lists PDE11A among the genes detected in PPNAD patients.
- name: PPNAD3
  display_name: "PPNAD3 (PDE8B)"
  description: >-
    PPNAD associated with variants in PDE8B, a high-affinity cAMP-specific
    phosphodiesterase. As with PDE11A, reduced cAMP degradation enhances
    cAMP/PKA signaling in adrenocortical cells.
  genes:
  - preferred_term: PDE8B
    term:
      id: hgnc:8794
      label: PDE8B
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5)
      were detected in the patients.
    explanation: >-
      Lists PDE8B among the genes detected in PPNAD patients.
- name: PPNAD4
  display_name: "PPNAD4 (PRKACA)"
  description: >-
    PPNAD associated with copy-number gain (amplification) of PRKACA, the PKA
    catalytic subunit alpha. Increased PRKACA dosage directly increases PKA
    catalytic activity. A germline PRKACA copy-number gain on chromosome
    19p13.13p13.12 was reported as a de novo cause of pediatric PPNAD.
  genes:
  - preferred_term: PRKACA
    term:
      id: hgnc:9380
      label: PRKACA
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a case of a female Chinese patient with PPNAD caused by the germline
      PRKACA gene copy number gain of chromosome 19.
    explanation: >-
      Documents PRKACA copy-number gain as a cause of PPNAD.
genetic:
- name: PRKAR1A
  gene_term:
    preferred_term: PRKAR1A
    term:
      id: hgnc:9388
      label: PRKAR1A
  association: Germline Inactivating Variants
  inheritance:
  - name: Autosomal Dominant
  notes: >-
    PRKAR1A encodes the type I alpha regulatory subunit of protein kinase A and
    is the most common cause of PPNAD; it is also the Carney complex type 1 gene.
    Many variants are premature stop codons leading to nonsense-mediated decay
    and haploinsufficiency, with a tumor-suppressor mechanism at the tissue level.
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The most common mutation was PKAR1A, accounting for 79.47% (120/151).
    explanation: >-
      Confirms PRKAR1A as the most frequently identified gene in tested PPNAD
      patients.
- name: PDE11A
  gene_term:
    preferred_term: PDE11A
    term:
      id: hgnc:8773
      label: PDE11A
  association: Reduced-Function Variants
  notes: >-
    PDE11A is a dual cAMP/cGMP phosphodiesterase; reduced-function variants
    diminish cAMP degradation and enhance cAMP/PKA signaling. PDE11A variants
    were detected in PPNAD patients, often co-occurring with PRKAR1A.
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5)
      were detected in the patients.
    explanation: >-
      Lists PDE11A among the pathogenic genes detected in PPNAD patients.
- name: PDE8B
  gene_term:
    preferred_term: PDE8B
    term:
      id: hgnc:8794
      label: PDE8B
  association: Reduced-Function Variants
  notes: >-
    PDE8B is a high-affinity cAMP-specific phosphodiesterase; reduced-function
    variants decrease cAMP degradation and increase cAMP/PKA signaling in
    adrenocortical cells.
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5)
      were detected in the patients.
    explanation: >-
      Lists PDE8B among the pathogenic genes detected in PPNAD patients.
- name: PRKACA
  gene_term:
    preferred_term: PRKACA
    term:
      id: hgnc:9380
      label: PRKACA
  association: Copy-Number Gain
  variant_origin: GERMLINE
  notes: >-
    PRKACA encodes the PKA catalytic subunit alpha. Germline copy-number gain
    (amplification) increases PKA catalytic activity and has been reported as a
    de novo cause of pediatric PPNAD.
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a rise in the copy number of the duplication-containing PRKACA gene on
      chromosome 19p13.13p13.12, a de novo but not heritable gene defect that
      causes disease.
    explanation: >-
      Documents germline PRKACA copy-number gain as a de novo cause of PPNAD.
phenotypes:
- name: ACTH-independent Cushing syndrome
  category: Laboratory
  description: >-
    PPNAD produces ACTH-independent (pituitary-independent) hypercortisolism,
    the defining biochemical and clinical feature, often with a paradoxical or
    absent response to dexamethasone suppression.
  phenotype_term:
    preferred_term: Primary hypercortisolism
    term:
      id: HP:0001579
      label: Primary hypercortisolism
  evidence:
  - reference: PMID:20548949
    reference_title: "Cushing's syndrome and fetal features resurgence in adrenal cortex-specific Prkar1a knockout mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      primary pigmented nodular adrenocortical disease (PPNAD), a bilateral
      adrenocortical hyperplasia causing pituitary-independent Cushing's
      syndrome.
    explanation: >-
      Defines PPNAD as causing pituitary-independent (ACTH-independent) Cushing
      syndrome.
- name: Increased circulating cortisol
  category: Laboratory
  description: >-
    Elevated cortisol with loss of normal circadian rhythm is a hallmark
    biochemical finding, reported in nearly all cases with available data.
  phenotype_term:
    preferred_term: Increased circulating cortisol level
    term:
      id: HP:0003118
      label: Increased circulating cortisol level
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the patient had diabetes, mild hypertension, low bone mass, a low ACTH
      level, and hypercortisolemia
    explanation: >-
      Case report documents hypercortisolemia in PPNAD.
- name: Decreased circulating ACTH
  category: Laboratory
  description: >-
    Low or undetectable ACTH reflects the ACTH-independent, autonomous adrenal
    source of cortisol and was reported in the majority of cases with data.
  phenotype_term:
    preferred_term: Decreased circulating ACTH concentration
    term:
      id: HP:0002920
      label: Decreased circulating ACTH concentration
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the patient had diabetes, mild hypertension, low bone mass, a low ACTH
      level, and hypercortisolemia
    explanation: >-
      Case report documents a low ACTH level consistent with ACTH-independent
      disease.
- name: Pigmented micronodular adrenocortical disease
  category: Histopathology
  description: >-
    The adrenal glands are small to normal in size and contain multiple small
    pigmented cortical nodules with internodular cortical atrophy, the defining
    pathological feature of PPNAD.
  phenotype_term:
    preferred_term: Pigmented micronodular adrenocortical disease
    term:
      id: HP:0001580
      label: Pigmented micronodular adrenocortical disease
  evidence:
  - reference: PMID:34680514
    reference_title: "Bilateral Adrenal Hyperplasia: Pathogenesis and Treatment."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Micronodular adrenal hyperplasia, including the primary pigmented
      micronodular adrenal dysplasia (PPNAD) and the isolated micronodular
      adrenal hyperplasia (iMAD), can be distinguished from the primary
      bilateral macronodular adrenal hyperplasia (PBMAH) according to the size
      of the nodules.
    explanation: >-
      Describes PPNAD as a micronodular form of bilateral adrenal hyperplasia,
      defined by its small (micronodular) cortical nodules in contrast to
      macronodular hyperplasia.
  - reference: PMID:16278264
    reference_title: "Serial analysis of gene expression in adrenocortical hyperplasia caused by a germline PRKAR1A mutation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      primary pigmented nodular adrenocortical disease (PPNAD) tissue from two
      adolescent female patients
    explanation: >-
      Confirms PPNAD adrenal pathology in patient tissue studied.
- name: Osteoporosis/Osteopenia
  category: Physical
  description: >-
    Reduced bone mineral density (osteoporosis or osteopenia) is among the most
    frequent complications, reported in 94.29% of cases in the pooled review,
    reflecting the catabolic effect of chronic hypercortisolism on bone.
  phenotype_term:
    preferred_term: Osteopenia
    term:
      id: HP:0000938
      label: Osteopenia
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      94.29% were combined with osteoporosis/osteopenia.
    explanation: >-
      Establishes osteoporosis/osteopenia as a very frequent feature of PPNAD,
      present in 94.29% of the pooled cohort, supporting the VERY_FREQUENT
      (80-99%) frequency band.
- name: Hypertension
  category: Physical
  description: >-
    Hypertension is a common cardiometabolic complication of chronic cortisol
    excess in PPNAD.
  phenotype_term:
    preferred_term: Hypertension
    term:
      id: HP:0000822
      label: Hypertension
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the patient had diabetes, mild hypertension, low bone mass, a low ACTH
      level, and hypercortisolemia
    explanation: >-
      Case report documents hypertension in a PPNAD patient.
- name: Weight gain
  category: Physical
  description: >-
    Weight gain and central obesity are typical manifestations of
    hypercortisolism in PPNAD.
  phenotype_term:
    preferred_term: Increased body weight
    term:
      id: HP:0004324
      label: Increased body weight
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The patient initially presented with kidney stones, short stature, and
      obesity.
    explanation: >-
      Case report documents obesity at presentation in a PPNAD patient.
- name: Diabetes mellitus
  category: Laboratory
  description: >-
    Glucose intolerance and diabetes mellitus occur as metabolic complications
    of cortisol excess.
  phenotype_term:
    preferred_term: Diabetes mellitus
    term:
      id: HP:0000819
      label: Diabetes mellitus
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      it was discovered that the patient had diabetes, mild hypertension, low
      bone mass, a low ACTH level, and hypercortisolemia
    explanation: >-
      Case report documents diabetes in a PPNAD patient.
- name: Short stature
  category: Physical
  description: >-
    In pediatric PPNAD, chronic hypercortisolism impairs linear growth, causing
    slow growth and short stature.
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: PMID:37988664
    reference_title: "Germline PRKACA amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Pediatric patients with PPNAD typically have unusual skin lesions and slow
      growth with unknown causes.
    explanation: >-
      Documents slow growth/short stature as typical in pediatric PPNAD.
- name: Spotty skin pigmentation (Carney complex)
  category: Physical
  description: >-
    In Carney-complex-associated PPNAD, spotty skin pigmentation (lentigines) is
    a frequent associated feature and correlates with PRKAR1A variants.
  phenotype_term:
    preferred_term: Multiple lentigines
    term:
      id: HP:0001003
      label: Multiple lentigines
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      There was a significant correlation between PRKAR1A pathogenic variant and
      spotty skin pigmentation in CNC concurrent with PPNAD (p < 0.05).
    explanation: >-
      Documents spotty skin pigmentation as a Carney-complex feature correlated
      with PRKAR1A variants in PPNAD.
treatments:
- name: Bilateral Adrenalectomy
  description: >-
    Bilateral adrenalectomy has historically been the definitive treatment for
    hypercortisolism in PPNAD, achieving cure of cortisol excess but requiring
    lifelong glucocorticoid and mineralocorticoid replacement. More recent
    practice increasingly favors unilateral or subtotal resection to avoid
    permanent adrenal insufficiency.
  treatment_term:
    preferred_term: adrenalectomy
    term:
      id: MAXO:0001030
      label: adrenalectomy
  evidence:
  - reference: PMID:34680514
    reference_title: "Bilateral Adrenal Hyperplasia: Pathogenesis and Treatment."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the treatment of bilateral adrenal hyperplasia will be discussed, focusing
      on current data on unilateral adrenalectomy.
    explanation: >-
      Review of treatment for bilateral adrenal hyperplasia including PPNAD;
      surgical resection is the mainstay, with current data increasingly
      favoring unilateral over bilateral adrenalectomy. This snippet supports
      adrenalectomy as the treatment modality but not bilateral resection as the
      preferred contemporary approach.
- name: Unilateral Adrenalectomy
  description: >-
    Unilateral adrenalectomy may be considered in selected patients, including
    women with fertility needs, although some cases require completion
    adrenalectomy if hypercortisolism persists or recurs.
  treatment_term:
    preferred_term: adrenalectomy
    term:
      id: MAXO:0001030
      label: adrenalectomy
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Unilateral adrenal resection may be considered as an option for women with
      fertility needs.
    explanation: >-
      Supports unilateral adrenalectomy as an option for fertility preservation.
- name: Steroidogenesis Inhibitor Pharmacotherapy
  description: >-
    Steroidogenesis inhibitors such as ketoconazole, metyrapone, and mitotane
    are used to control hypercortisolism as a bridge to surgery or in persistent
    or recurrent disease.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: ketoconazole
      term:
        id: CHEBI:47519
        label: ketoconazole
    - preferred_term: metyrapone
      term:
        id: CHEBI:44241
        label: metyrapone
    - preferred_term: mitotane
      term:
        id: CHEBI:6954
        label: Mitotane
  evidence:
  - reference: PMID:34680514
    reference_title: "Bilateral Adrenal Hyperplasia: Pathogenesis and Treatment."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the treatment of bilateral adrenal hyperplasia will be discussed, focusing
      on current data on unilateral adrenalectomy.
    explanation: >-
      This review covers the treatment of bilateral adrenal hyperplasia including
      PPNAD. The cited snippet establishes that the review addresses PPNAD
      treatment but focuses on adrenalectomy rather than pharmacotherapy;
      steroidogenesis inhibitors are standard pharmacologic options for
      hypercortisolism but are not specifically named in this snippet, so the
      support is indirect.
- name: Genetic Counseling
  description: >-
    Genetic counseling and cascade testing are recommended for families with
    PRKAR1A-related disease, together with surveillance for Carney complex
    manifestations such as cardiac myxoma.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:39006359
    reference_title: "The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients with PPNAD with spotty skin pigmentation should consider the
      PRKAR1A pathogenic variant and pay attention to CNC.
    explanation: >-
      Supports genetic evaluation and Carney complex surveillance in PPNAD with
      spotty skin pigmentation.
- name: Experimental mTORC1 Inhibition
  description: >-
    mTORC1 inhibition with rapamycin restored apoptosis sensitivity in the
    Prkar1a knockout mouse model, nominating mTORC1 as a candidate therapeutic
    target; this is an experimental, mechanism-informed direction rather than
    standard care.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: sirolimus
      term:
        id: CHEBI:9168
        label: sirolimus
  evidence:
  - reference: PMID:24865460
    reference_title: "mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD)."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      mTOR pathway is activated by PKA in adrenocortical cells and participates
      in vivo to apoptosis resistance in primary pigmented nodular
      adrenocortical disease (PPNAD)
    explanation: >-
      Provides the in vivo rationale for mTORC1 inhibition as an experimental
      therapy in PPNAD.
- name: Experimental KIT Inhibition
  description: >-
    KIT inhibition with imatinib reduced viability and induced apoptosis in
    PRKAR1A-deficient adrenocortical cells and inhibited xenograft growth,
    suggesting c-KIT inhibitors as a possible alternative therapy when other
    treatments are not optimal; this remains experimental.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: imatinib
      term:
        id: CHEBI:45783
        label: imatinib
  evidence:
  - reference: PMID:32738126
    reference_title: "c-KIT oncogene expression in PRKAR1A-mutant adrenal cortex."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      c-KIT inhibition decreased growth, suggesting that c-KIT inhibitors may be
      a reasonable alternative therapy to be tested in PPNAD, when other
      treatments are not optimal.
    explanation: >-
      Provides the experimental rationale for KIT inhibition as an alternative
      therapy in PPNAD.
clinical_trials:
- name: NCT00001452
  status: RECRUITING
  description: >-
    NIH observational study defining the genotype and clinical phenotype of
    PPNAD, Carney complex, and related conditions, including genetic basis,
    molecular tumor changes, carrier identification, and prognosis.
  evidence:
  - reference: clinicaltrials:NCT00001452
    reference_title: "Definition of the Genotype and Clinical Phenotype of Primary Pigmented Nodular Adrenocortical Disease (PPNAD), Carney Complex, Peutz-Jeghers Syndrome and Related Conditions"
    supports: SUPPORT
    snippet: >-
      Primary pigmented nodular adrenocortical disease (PPNAD) is a
      pituitary-independent, primary adrenal form of hypercortisolism
    explanation: >-
      The trial summary characterizes PPNAD as pituitary-independent primary
      adrenal hypercortisolism, the disease under study.
classifications:
  harrisons_chapter:
  - classification_value: ENDOCRINOLOGY_METABOLISM
datasets: []

📚

References & Deep Research

Deep Research

1

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Primary Pigmented Nodular Adrenocortical Disease (PPNAD): Disease Characteristics Research Report

Edison Scientific Literature 53 citations 2026-06-05T14:59:02.223744

Primary Pigmented Nodular Adrenocortical Disease (PPNAD): Disease Characteristics Research Report

Target disease: Primary Pigmented Nodular Adrenocortical Disease (PPNAD)
Category: Mendelian adrenal hyperfunction disorder causing ACTH-independent Cushing syndrome
MONDO ID / OMIM / Orphanet / MeSH / ICD-10/11: Not retrieved with the available tools in this run; requires direct lookup in OMIM/Orphanet/MONDO/MeSH/ICD resources. (sun2024theclinicalcharacteristics pages 1-2)

Executive summary (current understanding)

PPNAD is a rare, typically bilateral micronodular adrenocortical disease that produces cortisol autonomously (ACTH-independent / pituitary-independent hypercortisolism) and often presents in childhood or young adulthood. It can occur as an isolated condition or as the most common endocrine manifestation of Carney complex (CNC). The dominant mechanistic paradigm is dysregulated cAMP–PKA signaling (most often due to loss-of-function PRKAR1A), driving autonomous steroidogenesis, abnormal adrenal differentiation, increased proliferation, and resistance to apoptosis; downstream pathway involvement includes mTORC1 and Wnt signaling, with translational hypotheses for targeted therapy (e.g., mTORC1 inhibition; KIT inhibition) supported by experimental models. (sun2024theclinicalcharacteristics pages 1-2, sahutbarnola2010cushingssyndromeand pages 1-2, joussineau2014mtorpathwayis pages 1-2, almeida2012activationofcyclic pages 6-6, nadella2020ckitoncogeneexpression pages 1-3)

1. Disease information

1.1 Definition and overview

Human clinical / aggregated evidence.
PPNAD is a rare cause of endogenous Cushing syndrome (CS) due to primary adrenal, ACTH-independent cortisol excess. In a 2024 systematic review, PPNAD is described as a rare cause of endogenous CS affecting children and young adults and characterized histologically by multiple pigmented micronodules. (sun2024theclinicalcharacteristics pages 1-2)

A classic transcriptomic study defines PPNAD as: “another form of bilateral adrenocortical hyperplasia that is often associated with ACTH-independent Cushing’s syndrome and is characterized by small to normal-sized adrenal glands containing multiple small cortical pigmented nodules.” (PMID not available in tool output; J Clin Endocrinol Metab, Feb 2006; URL: https://doi.org/10.1210/jc.2005-1301) (horvath2006serialanalysisof pages 1-1)

The NIH observational protocol similarly characterizes PPNAD as a pituitary-independent primary adrenal hypercortisolism with dexamethasone resistance, loss of diurnal rhythm, and distinctive bilateral histopathology including pigmented nodules and extranodular cortical atrophy. (ClinicalTrials.gov NCT00001452; first posted 1995-12-14; URL: https://clinicaltrials.gov/study/NCT00001452) (NCT00001452 chunk 1)

1.2 Synonyms / alternative names

From the 2024 systematic review: “PPNAD … also termed i-PPNAD, familial isolated PPNAD, isolated PPNAD or micronodular adrenal disease.” (sun2024theclinicalcharacteristics pages 1-2)

1.3 Data provenance

Evidence in this report is derived from: - Aggregated disease-level sources: systematic review of 210 published cases (Sun et al., 2024). (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5) - Individual patient reports/series: e.g., PRKACA amplification case report (2024) and a 5-patient case series (2006). (yang2024germlineprkacaamplificationassociated pages 2-4, zhu2006primarypigmentednodular pages 1-2) - Experimental models: adrenal cortex–specific Prkar1a knockout mouse, cell lines, xenografts. (sahutbarnola2010cushingssyndromeand pages 1-2, nadella2020ckitoncogeneexpression pages 1-3, joussineau2014mtorpathwayis pages 1-2)

2. Etiology

2.1 Disease causal factors

Primary cause: Mendelian or mosaic genetic dysregulation of cAMP/PKA signaling leading to autonomous cortisol production via bilateral micronodular adrenal disease (PPNAD). (chevalier2021bilateraladrenalhyperplasia pages 1-3, robinsonwhite2006prkar1amutationsandprotein pages 1-2)

Major causal/associated genes in recent aggregated evidence (2024): PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, ARMC5 were reported among genetically tested PPNAD cases, with PRKAR1A predominant. (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)

2.2 Risk factors

Genetic risk factors (causal genes / susceptibility): - PRKAR1A pathogenic variants (most common in tested PPNAD cases; see Section 4). (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5) - PDE11A variants (often co-occurring with PRKAR1A in the 2024 review). (sun2024theclinicalcharacteristics pages 4-5) - PRKACA copy-number gain/amplification reported as a causal event in at least one pediatric case report. (yang2024germlineprkacaamplificationassociated pages 2-4)

Non-genetic risk factors: No robust environmental/lifestyle risk factors were identified in the evidence retrieved for this run; PPNAD is primarily genetic. (chevalier2021bilateraladrenalhyperplasia pages 1-3)

2.3 Protective factors

No protective genetic or environmental factors were identified in the retrieved evidence. (sun2024theclinicalcharacteristics pages 1-2)

2.4 Gene–environment interactions

Not established in the retrieved evidence; currently appears primarily genotype-driven. (sun2024theclinicalcharacteristics pages 1-2)

3. Phenotypes (clinical spectrum)

3.1 Core phenotype: ACTH-independent Cushing syndrome / hypercortisolism

Key features (HPO suggestions in parentheses): - Hypercortisolism with loss of circadian rhythm (Abnormal circulating cortisol concentration [HP:0008207]; Abnormality of circadian rhythm [HP:0001270 as proxy]; Cushing syndrome [HP:0000863]). Loss of cortisol rhythm was reported in 98.59% (70/71) of cases with data in the 2024 systematic review. (sun2024theclinicalcharacteristics pages 4-5) - Low/undetectable ACTH (Decreased circulating ACTH level [no exact HPO term; use Abnormality of pituitary hormone level HP:0000851 + ACTH annotation]) reported in 78.57% (77/98). (sun2024theclinicalcharacteristics pages 4-5) - Classical Cushingoid appearance: moon facies, buffalo hump, plethora, violaceous striae (e.g., Moon facies [HP:0000270], Dorsocervical fat pad [HP:0002775], Facial plethora [HP:0031307], Purple striae [HP:0001055]). (zhu2006primarypigmentednodular pages 1-2)

Course: PPNAD may be mild, subclinical, or cyclic in some cases (not consistently quantified in the retrieved evidence). (NCT00001452 chunk 1)

3.2 Skeletal phenotype

Osteoporosis/osteopenia (Osteoporosis [HP:0000939], Osteopenia [HP:0012055]) in 94.29% (33/35) in the 2024 systematic review. (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)

3.3 Cardiometabolic phenotype

Hypertension (Hypertension [HP:0000822]) in 67.50% (81/120). (sun2024theclinicalcharacteristics pages 4-5)
Weight gain/obesity (Weight gain [HP:0004324], Obesity [HP:0001513]) in 59.17% (71/120). (sun2024theclinicalcharacteristics pages 4-5)
Diabetes/impaired glucose tolerance reported in case series and case report (HPO: Diabetes mellitus [HP:0000819], Impaired glucose tolerance [HP:0001959]). (zhu2006primarypigmentednodular pages 1-2, yang2024germlineprkacaamplificationassociated pages 2-4)

3.4 Pigmentary / syndromic features (Carney complex association)

Among PPNAD patients in the 2024 review, 31.43% (66/210) had concurrent CNC; among these, 71.21% (47/66) had spotty skin pigmentation (HPO: Lentigines [HP:0001003], Hyperpigmentation [HP:0000953]). (sun2024theclinicalcharacteristics pages 4-5)

3.5 Quality-of-life impact

Direct QoL instrument data (SF-36/EQ-5D/PROMIS) were not identified in the retrieved sources. Clinically, the high frequency of osteoporosis, hypertension, and metabolic disease implies substantial morbidity in untreated hypercortisolism. (sun2024theclinicalcharacteristics pages 4-5)

4. Genetic / molecular information

4.1 Causal genes and inheritance

Inheritance: Often autosomal dominant in the context of PRKAR1A-related CNC/PPNAD (tumor-suppressor model with haploinsufficiency/second hit described in reviews). (chevalier2021bilateraladrenalhyperplasia pages 6-7, chevalier2021bilateraladrenalhyperplasia pages 1-3)

Genes implicated in the 2024 systematic review (151 tested; 132 with pathogenic variants): PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, ARMC5; PRKAR1A was most frequent (79.47%). (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)

High-yield statistic: In the 2024 review, genetic testing had 87.42% (132/151) yield for a pathogenic variant in reported cases. (sun2024theclinicalcharacteristics pages 1-2)

4.2 Pathogenic variants and functional classes

PRKAR1A loss-of-function: Reviews describe many PRKAR1A mutations as premature stop codons leading to nonsense-mediated decay and haploinsufficiency; other mutations may generate altered proteins (some degraded; some potentially dominant-negative). (chevalier2021bilateraladrenalhyperplasia pages 6-7)
PRKACA amplification (copy-number gain): A 2024 case report describes germline PRKACA copy-number gain on chr19p13.13p13.12 associated with pediatric-onset PPNAD and CNC features. (yang2024germlineprkacaamplificationassociated pages 1-2, yang2024germlineprkacaamplificationassociated pages 2-4)

Population allele frequency / gnomAD / ClinVar classifications: Not retrievable in this run because ClinVar/gnomAD tools were not available.

4.3 Genotype–phenotype association

Sun et al. (2024) reports a significant association between PRKAR1A pathogenic variants and spotty skin pigmentation in CNC with concurrent PPNAD. (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)

5. Environmental information

No specific environmental toxins, lifestyle exposures, or infectious triggers were identified in the retrieved evidence. Current literature captured here supports PPNAD as primarily a genetic disease driven by cAMP/PKA pathway dysregulation. (chevalier2021bilateraladrenalhyperplasia pages 1-3)

6. Mechanism / pathophysiology

6.1 Core pathway: cAMP–PKA dysregulation (upstream → downstream causal chain)

Upstream trigger: Germline inactivating PRKAR1A (PKA regulatory subunit RIα) or other cAMP/PKA pathway alterations. (chevalier2021bilateraladrenalhyperplasia pages 6-7, chevalier2021bilateraladrenalhyperplasia pages 1-3)

Cellular consequence: Increased PKA catalytic activity and altered signaling, leading to autonomous cortisol production and adrenal hyperplasia.

In vivo mechanistic evidence (mouse model): In adrenal cortex–specific Prkar1a knockout (AdKO) mice, PRKAR1A loss caused increased PKA activity and pituitary-independent Cushing syndrome, with autonomous steroidogenic gene expression, deregulated differentiation, increased proliferation, and resistance to apoptosis. The abstract explicitly states: “AdKO mice develop pituitary-independent Cushing's syndrome with increased PKA activity.” (PLoS Genet, Jun 2010; URL: https://doi.org/10.1371/journal.pgen.1000980) (sahutbarnola2010cushingssyndromeand pages 1-2)

Ontology suggestions: - GO Biological Process: cAMP-mediated signaling (GO:0019933), protein kinase A signaling (GO:?), steroid biosynthetic process (GO:0006694), regulation of apoptotic process (GO:0042981), cell proliferation (GO:0008283). - Cell types (CL): adrenocortical cell (use CL term for adrenal cortical cell), steroidogenic cell.

6.2 mTORC1 activation and apoptosis resistance

A mechanistic study reports that mTOR pathway is activated by PKA in adrenocortical cells and contributes to apoptosis resistance in PPNAD; BAD phosphorylation is highlighted as a downstream effector, and rapamycin (mTORC1 inhibitor) restored apoptosis sensitivity in vivo in the mouse model. (Hum Mol Genet, Oct 2014; URL: https://doi.org/10.1093/hmg/ddu265) (joussineau2014mtorpathwayis pages 1-2)

Translational implication: mTORC1 is a candidate therapeutic target for PPNAD when surgery is not optimal (hypothesis supported by mechanistic in vivo work). (joussineau2014mtorpathwayis pages 1-2)

6.3 KIT/SCF as a potential therapeutic axis

In PRKAR1A-mutant PPNAD tissue, c-KIT and SCF are upregulated in certain nodular areas; in vitro, PRKAR1A deficiency and forskolin-induced cAMP signaling increased c-KIT expression, and PRKACA knockdown reduced it. KIT inhibition with imatinib reduced growth and induced apoptosis in a PRKAR1A-deficient adrenocortical cell line and inhibited growth in xenografts. (Endocr Relat Cancer, Oct 2020; URL: https://doi.org/10.1530/erc-20-0270) (nadella2020ckitoncogeneexpression pages 1-3)

6.4 Wnt/cell-cycle programs downstream of PRKAR1A defects

Transcriptomic/pathway analyses in PRKAR1A-mutant adrenal lesions show overexpression of Wnt pathway genes (e.g., CCND1, CTNNB1, LEF1, LRP5) and cell-cycle regulators, supporting Wnt-linked proliferative programs downstream of cAMP/PKA activation in PPNAD. (J Clin Endocrinol Metab, Apr 2012; URL: https://doi.org/10.1210/jc.2011-3000) (almeida2012activationofcyclic pages 6-6)

Omics datapoint (SAGE): The 2006 SAGE study reported increased expression in PPNAD of steroidogenesis-related genes including steroidogenic acute regulator and steroidogenic enzymes CYP17A1 and CYP21A2. (URL: https://doi.org/10.1210/jc.2005-1301) (horvath2006serialanalysisof pages 1-1)

7. Anatomical structures affected

7.1 Primary organ

Adrenal cortex (bilateral) (UBERON suggestion: adrenal gland UBERON:0002369; adrenal cortex subregion). PPNAD is characterized by multiple small pigmented nodules with extranodular cortical atrophy. (sun2024theclinicalcharacteristics pages 1-2, NCT00001452 chunk 1)

7.2 Secondary system involvement (complications of hypercortisolism)

Skeletal system: osteoporosis/osteopenia. (sun2024theclinicalcharacteristics pages 4-5)
Cardiovascular/metabolic systems: hypertension, diabetes/metabolic syndrome features. (sun2024theclinicalcharacteristics pages 4-5, zhu2006primarypigmentednodular pages 1-2)

7.3 Subcellular/cellular compartments

Not specifically described in retrieved evidence; however, pathway data imply cytosolic/nuclear PKA signaling and mTORC1 signaling complexes (GO Cellular Component suggestions: cytosol, nucleus, mTOR complex 1).

8. Temporal development

Typical onset: childhood to young adulthood; in Sun et al. 2024, 71.88% were 10–30 years. (sun2024theclinicalcharacteristics pages 4-5)
Course: can be prolonged and misdiagnosed; diagnostic difficulty emphasized in systematic review and NIH protocol. (sun2024theclinicalcharacteristics pages 1-2, NCT00001452 chunk 1)

9. Inheritance and population

9.1 Epidemiology

Precise prevalence/incidence estimates were not identified in the retrieved sources.

A 2006 clinical review/case series stated PPNAD accounts for ~0.6%–1.9% of all Cushing syndrome (statement within that article’s text; not independently validated here). (Chinese Medical Journal, May 2006; URL: https://doi.org/10.1097/00029330-200605010-00015) (zhu2006primarypigmentednodular pages 2-4)

9.2 Demographics (from 2024 systematic review)

Median age 22; female:male 2:1. (sun2024theclinicalcharacteristics pages 1-2)

10. Diagnostics

10.1 Clinical and laboratory tests

Key biochemical findings: - Elevated cortisol with loss of circadian rhythm (98.59% where reported). (sun2024theclinicalcharacteristics pages 4-5) - Low/undetectable ACTH (78.57% where reported). (sun2024theclinicalcharacteristics pages 4-5)

Paradoxical / absent dexamethasone suppression: In the 2024 systematic review, 31/31 (100%) with reported testing had no suppression or paradoxical increase on high-dose dexamethasone/Liddle-type testing. (sun2024theclinicalcharacteristics pages 4-5)

Example case report wording: “LDDST and HDDST revealed that the patient’s UFC level was not inhibited… indicating a paradoxical increase.” (Archives Endocrinol Metab, Jan 2024; URL: https://doi.org/10.20945/2359-4292-2022-0491) (yang2024germlineprkacaamplificationassociated pages 2-4)

10.2 Imaging

Imaging may be subtle; small bilateral nodules may be seen on MRI/CT in some cases (e.g., “multiple small adrenal nodules” in a CNC case report; bilateral thickening/nodular change ~10 mm in PRKACA amplification case). (yang2024germlineprkacaamplificationassociated pages 2-4)

10.3 Pathology

2024 systematic review/WHO 2022-oriented description: multiple beaded pigmented micronodules (<10 mm, often 2–5 mm), CYP11B1 positivity confirming cortisol production, and inter-nodular cortical atrophy. (sun2024theclinicalcharacteristics pages 1-2)

NIH protocol: pigmented nodular adenomas with loss of normal zonation and extranodular cortical atrophy. (NCT00001452 chunk 1)

10.4 Genetic testing strategy

Given high yield in the systematic review (87.42% of tested patients), Sun et al. recommend considering genetic testing prior to surgery due to diagnostic difficulty and syndromic implications (CNC surveillance). (sun2024theclinicalcharacteristics pages 1-2)

10.5 Differential diagnosis

Not comprehensively extracted in this run; key differentiations include other causes of ACTH-independent Cushing syndrome (e.g., cortisol-producing adenoma; PBMAH) and ACTH-dependent Cushing disease. (NCT00001452 chunk 1)

11. Outcome / prognosis

Long-term outcome statistics (survival, mortality, QoL scores) were not identified in the retrieved evidence.
The NIH protocol emphasizes the need to “establish prognosis for carriers/affected individuals,” highlighting that natural history is an ongoing research aim. (NCT00001452 chunk 1)

Complications expected from chronic hypercortisolism include osteoporosis, hypertension, diabetes, and thromboembolic risk in CNC due to myxomas; embolism rates are discussed in the 2024 review in the context of recurrent myxomas (not PPNAD-specific mortality). (sun2024theclinicalcharacteristics pages 11-12)

12. Treatment

12.1 Surgical (real-world implementation)

Surgery is the dominant real-world definitive therapy for cortisol excess.

In Sun et al. 2024 (patients with reported surgery data, n=122): - Bilateral adrenalectomy: 50.82% (62/122) - Unilateral adrenalectomy: 33.61% (41/122) - Two-stage bilateral adrenalectomy: 12.30% (15/122)

Unilateral adrenalectomy was discussed as an option in selected patients (including fertility considerations), but some unilateral cases required completion because hypercortisolism persisted/returned. (sun2024theclinicalcharacteristics pages 4-5, sun2024theclinicalcharacteristics pages 12-14)

MAXO suggestions: adrenalectomy (MAXO term for adrenalectomy), unilateral adrenalectomy, bilateral adrenalectomy.

12.2 Pharmacotherapy for hypercortisolism (bridging or recurrence)

Sun et al. list steroidogenesis inhibitors used in persistent/recurrent hypercortisolism: ketoconazole, metyrapone, mitotane, trilostane, and note fluconazole proposed as a safer alternative to ketoconazole in some contexts. (sun2024theclinicalcharacteristics pages 11-12)

MAXO suggestions: pharmacological inhibition of steroid biosynthesis; glucocorticoid replacement therapy (post-bilateral adrenalectomy).

12.3 Targeted/experimental therapeutics (mechanism-informed)

mTORC1 inhibition (rapamycin): restored apoptosis sensitivity in vivo in a mouse model, supporting mTORC1 as a candidate target. (joussineau2014mtorpathwayis pages 1-2)
KIT inhibition (imatinib): reduced growth and induced apoptosis in PRKAR1A-deficient adrenocortical cells and inhibited xenograft growth. (nadella2020ckitoncogeneexpression pages 1-3)

These are not established standard-of-care treatments for PPNAD but represent translational directions grounded in mechanistic evidence.

12.4 Clinical trials

No interventional trials specific to PPNAD were identified in the retrieved clinical trial set; however, an NIH cohort study focused on PPNAD/CNC genetics and natural history enrolled 1,387 participants (NCT00001452; initiated 1995-12-14). (NCT00001452 chunk 1)

13. Prevention

Primary prevention is not currently established because PPNAD is primarily genetic.

Secondary prevention / early detection: Genetic counseling and cascade testing in families with PRKAR1A-related disease and surveillance for CNC manifestations are supported conceptually; the NIH protocol notes that “there are no standardized screening tests” for family members at present (historical context, 1995 protocol). (NCT00001452 chunk 1)

14. Other species / natural disease

No naturally occurring veterinary/other-species PPNAD analogs were identified in the retrieved evidence.

15. Model organisms

Adrenal cortex–specific Prkar1a knockout mouse (AdKO): recapitulates key human features (ACTH-independent Cushing syndrome, bilateral adrenal hyperplasia) and provides in vivo evidence that PRKAR1A loss is sufficient for PPNAD-like disease. (PLoS Genet, Jun 2010; https://doi.org/10.1371/journal.pgen.1000980) (sahutbarnola2010cushingssyndromeand pages 1-2)

Mechanism-focused mouse work: AdKO model used to show PKA→mTORC1 activation contributing to apoptosis resistance; rapamycin reversed apoptosis resistance in vivo. (joussineau2014mtorpathwayis pages 1-2)

Cellular/xenograft systems: PRKAR1A-deficient adrenocortical cell lines (e.g., CAR47) and H295 xenografts used to test KIT inhibition (imatinib). (nadella2020ckitoncogeneexpression pages 1-3)

Recent developments (prioritizing 2023–2024)

1) Largest recent synthesis of clinical/genetic data: Systematic review of 210 PPNAD patients (Jun 2024) quantifying phenotype frequencies, gene frequencies, and surgical patterns; highlights diagnostic yield of genetic testing and pregnancy/fertility considerations for unilateral adrenalectomy. (https://doi.org/10.3389/fendo.2024.1356870; Jun 2024) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)

2) PRKACA copy-number gain as a causal mechanism: 2024 case report describing germline PRKACA amplification-associated PPNAD with paradoxical dexamethasone response and micronodular pathology; reinforces expansion of genetic causes beyond PRKAR1A. (https://doi.org/10.20945/2359-4292-2022-0491; Jan 2024) (yang2024germlineprkacaamplificationassociated pages 2-4)

Key quantitative evidence table (Sun et al., 2024)

Domain	Variable	Numerator/Denominator	Frequency / Value	Notes
Cohort	Total patients included	210/210	210 patients	Systematic review cohort size; median age 22 years (Sun et al., Frontiers in Endocrinology, Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 1-2)
Demographics	Female:male ratio	—	2:1	Female predominance in pooled cohort; most patients were 10–30 years old (71.88%) (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Demographics	Age distribution 10–30 years	—	71.88%	Majority presented in adolescence/young adulthood (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 4-5)
Carney complex association	Concurrent Carney complex (CNC)	66/210	31.43%	cPPNAD/CNC subset in pooled review (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
CNC phenotype	Spotty skin pigmentation among cPPNAD/CNC	47/66	71.21%	Pigmentary findings common in CNC-associated cases; supports PRKAR1A testing consideration (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5, sun2024theclinicalcharacteristics pages 12-14)
CNC phenotype	Cardiac or cutaneous myxoma among cPPNAD/CNC	19/66	28.79%	Relevant for surveillance due to embolic risk in CNC (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 11-12)
Major phenotype	Osteoporosis / osteopenia	33/35	94.29%	One of the most frequent reported morbidity features (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Major phenotype	Hypertension	81/120	67.50%	Common hypercortisolism-related comorbidity (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Major phenotype	Weight gain	71/120	59.17%	Typical Cushing syndrome manifestation in pooled cases (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Diagnostic laboratory	Loss of cortisol circadian rhythm	70/71	98.59%	Strong biochemical hallmark of hypercortisolism (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 4-5)
Diagnostic laboratory	Low/undetectable ACTH	77/98	78.57%	Consistent with ACTH-independent Cushing syndrome (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Diagnostic laboratory	Plasma cortisol not suppressed on dexamethasone testing	31/31	100%	Included paradoxical or absent suppression on low-/high-dose dexamethasone/Liddle-type testing (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Genetics	Patients undergoing genetic testing	151/210	71.90%	Not all published cases had molecular testing (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 12-14)
Genetics	Any pathogenic variant detected	132/151	87.42%	High diagnostic yield in tested cases (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Genetics	Genes reported in cohort	—	6 genes	PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, ARMC5 (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Genetics	PRKAR1A pathogenic variants	120/151	79.47%	Most common implicated gene in tested patients (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Genetics	PDE11A variants	40/151	26.49%	Some patients carried PDE11A along with PRKAR1A (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Genetics	PRKAR1A + PDE11A co-occurrence	33/151	21.85%	Reported overlap among genetically tested cases (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Genotype-phenotype	Spotty pigmentation with PRKAR1A variant among evaluable CNC cases	33/45	73.33%	Significant association reported between PRKAR1A and spotty skin pigmentation in CNC with PPNAD (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 1-2, sun2024theclinicalcharacteristics pages 4-5)
Surgery	Any surgery data available	122/210	58.10%	Surgical approach reported for subset of pooled cases (Sun et al., Jun 2024, https://doi.org/10.3389/fendo.2024.1356870) (sun2024theclinicalcharacteristics pages 4-5)
Surgery	Bilateral adrenalectomy	62/122	50.82%	Most common surgical treatment in reported cases (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)
Surgery	Unilateral adrenalectomy	41/122	33.61%	Considered in selected patients; review discusses fertility/pregnancy considerations (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5, sun2024theclinicalcharacteristics pages 12-14)
Surgery	Two-stage bilateral adrenalectomy	15/122	12.30%	Often reflects completion adrenalectomy after initial unilateral approach (Sun et al., Jun 2024, DOI above) (sun2024theclinicalcharacteristics pages 4-5)

Table: This table compiles the main quantitative findings from Sun et al. 2024’s systematic review of 210 PPNAD patients, including demographics, phenotype frequencies, diagnostic findings, genetic results, and surgery patterns. It is useful as a concise evidence summary for knowledge-base curation and clinical overview.

References

(sun2024theclinicalcharacteristics pages 1-2): Julian Sun, Lin Ding, Liping He, Hang Fu, Rui Li, Jing Feng, Jianjun Dong, and Lin Liao. The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review. Frontiers in Endocrinology, Jun 2024. URL: https://doi.org/10.3389/fendo.2024.1356870, doi:10.3389/fendo.2024.1356870. This article has 12 citations.
(sahutbarnola2010cushingssyndromeand pages 1-2): Isabelle Sahut-Barnola, Cyrille de Joussineau, Pierre Val, Sarah Lambert-Langlais, Christelle Damon, Anne-Marie Lefrançois-Martinez, Jean-Christophe Pointud, Geoffroy Marceau, Vincent Sapin, Frédérique Tissier, Bruno Ragazzon, Jérôme Bertherat, Lawrence S. Kirschner, Constantine A. Stratakis, and Antoine Martinez. Cushing's syndrome and fetal features resurgence in adrenal cortex–specific prkar1a knockout mice. PLoS Genetics, 6:e1000980, Jun 2010. URL: https://doi.org/10.1371/journal.pgen.1000980, doi:10.1371/journal.pgen.1000980. This article has 128 citations and is from a domain leading peer-reviewed journal.
(joussineau2014mtorpathwayis pages 1-2): Cyrille de Joussineau, Isabelle Sahut-Barnola, Frédérique Tissier, Typhanie Dumontet, Coralie Drelon, Marie Batisse-Lignier, Igor Tauveron, Jean-Christophe Pointud, Anne-Marie Lefrançois-Martinez, Constantine A. Stratakis, Jérôme Bertherat, Pierre Val, and Antoine Martinez. Mtor pathway is activated by pka in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (ppnad). Human molecular genetics, 23 20:5418-28, Oct 2014. URL: https://doi.org/10.1093/hmg/ddu265, doi:10.1093/hmg/ddu265. This article has 48 citations and is from a domain leading peer-reviewed journal.
(almeida2012activationofcyclic pages 6-6): Madson Q. Almeida, Monalisa F. Azevedo, Paraskevi Xekouki, Eirini I. Bimpaki, Anelia Horvath, Michael T. Collins, Lefkothea P. Karaviti, George S. Jeha, Nisan Bhattacharyya, Chris Cheadle, Tonya Watkins, Isabelle Bourdeau, Maria Nesterova, and Constantine A. Stratakis. Activation of cyclic amp signaling leads to different pathway alterations in lesions of the adrenal cortex caused by germline prkar1a defects versus those due to somatic gnas mutations. The Journal of Clinical Endocrinology & Metabolism, 97:E687-E693, Apr 2012. URL: https://doi.org/10.1210/jc.2011-3000, doi:10.1210/jc.2011-3000. This article has 71 citations.
(nadella2020ckitoncogeneexpression pages 1-3): Kiran Nadella, Fabio R Faucz, and Constantine A Stratakis. C-kit oncogene expression in prkar1a-mutant adrenal cortex. Oct 2020. URL: https://doi.org/10.1530/erc-20-0270, doi:10.1530/erc-20-0270. This article has 1 citations and is from a domain leading peer-reviewed journal.
(horvath2006serialanalysisof pages 1-1): Anelia Horvath, Ludmila Mathyakina, Queenie Vong, Vanessa Baxendale, Alan L. Y. Pang, Wai-Yee Chan, and Constantine A. Stratakis. Serial analysis of gene expression in adrenocortical hyperplasia caused by a germline prkar1a mutation. The Journal of clinical endocrinology and metabolism, 91 2:584-96, Feb 2006. URL: https://doi.org/10.1210/jc.2005-1301, doi:10.1210/jc.2005-1301. This article has 71 citations.
(NCT00001452 chunk 1): Defining the Genetic Basis for the Development of Primary Pigmented Nodular Adrenocortical Disease (PPNAD) and the Carney Complex. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). 1995. ClinicalTrials.gov Identifier: NCT00001452
(sun2024theclinicalcharacteristics pages 4-5): Julian Sun, Lin Ding, Liping He, Hang Fu, Rui Li, Jing Feng, Jianjun Dong, and Lin Liao. The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review. Frontiers in Endocrinology, Jun 2024. URL: https://doi.org/10.3389/fendo.2024.1356870, doi:10.3389/fendo.2024.1356870. This article has 12 citations.
(yang2024germlineprkacaamplificationassociated pages 2-4): Wang-Rong Yang, Xing-Huan Liang, Ying-Fen Qin, Hai-Yan Yang, Shu-Zhan He, Zhen-Xing Huang, Yu-Ping Liu, and Zuo-Jie Luo. Germline prkaca amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review. Archives of Endocrinology and Metabolism, Jan 2024. URL: https://doi.org/10.20945/2359-4292-2022-0491, doi:10.20945/2359-4292-2022-0491. This article has 8 citations.
(zhu2006primarypigmentednodular pages 1-2): Yu ZHU, Yu-xuan WU, Wen-bin RUI, Ding-yi LIU, Wen-long ZHOU, Rong-ming ZHANG, Fu-kang SUN, Chong-yu ZHANG, and Zhou-jun SHEN. Primary pigmented nodular adrenocortical disease. Chinese Medical Journal, 119(9):782-785, May 2006. URL: https://doi.org/10.1097/00029330-200605010-00015, doi:10.1097/00029330-200605010-00015. This article has 2 citations and is from a peer-reviewed journal.
(chevalier2021bilateraladrenalhyperplasia pages 1-3): Benjamin Chevalier, Marie-Christine Vantyghem, and Stéphanie Espiard. Bilateral adrenal hyperplasia: pathogenesis and treatment. Biomedicines, 9:1397, Oct 2021. URL: https://doi.org/10.3390/biomedicines9101397, doi:10.3390/biomedicines9101397. This article has 35 citations.
(robinsonwhite2006prkar1amutationsandprotein pages 1-2): Audrey Robinson-White, Elise Meoli, Sotirios Stergiopoulos, Anelia Horvath, Sosipatros Boikos, Ioannis Bossis, and Constantine A. Stratakis. prkar1amutations and protein kinase a interactions with other signaling pathways in the adrenal cortex. The Journal of Clinical Endocrinology & Metabolism, 91:2380-2388, Jun 2006. URL: https://doi.org/10.1210/jc.2006-0188, doi:10.1210/jc.2006-0188. This article has 83 citations.
(chevalier2021bilateraladrenalhyperplasia pages 6-7): Benjamin Chevalier, Marie-Christine Vantyghem, and Stéphanie Espiard. Bilateral adrenal hyperplasia: pathogenesis and treatment. Biomedicines, 9:1397, Oct 2021. URL: https://doi.org/10.3390/biomedicines9101397, doi:10.3390/biomedicines9101397. This article has 35 citations.
(yang2024germlineprkacaamplificationassociated pages 1-2): Wang-Rong Yang, Xing-Huan Liang, Ying-Fen Qin, Hai-Yan Yang, Shu-Zhan He, Zhen-Xing Huang, Yu-Ping Liu, and Zuo-Jie Luo. Germline prkaca amplification-associated primary pigmented nodular adrenocortical disease: a case report and literature review. Archives of Endocrinology and Metabolism, Jan 2024. URL: https://doi.org/10.20945/2359-4292-2022-0491, doi:10.20945/2359-4292-2022-0491. This article has 8 citations.
(zhu2006primarypigmentednodular pages 2-4): Yu ZHU, Yu-xuan WU, Wen-bin RUI, Ding-yi LIU, Wen-long ZHOU, Rong-ming ZHANG, Fu-kang SUN, Chong-yu ZHANG, and Zhou-jun SHEN. Primary pigmented nodular adrenocortical disease. Chinese Medical Journal, 119(9):782-785, May 2006. URL: https://doi.org/10.1097/00029330-200605010-00015, doi:10.1097/00029330-200605010-00015. This article has 2 citations and is from a peer-reviewed journal.
(sun2024theclinicalcharacteristics pages 11-12): Julian Sun, Lin Ding, Liping He, Hang Fu, Rui Li, Jing Feng, Jianjun Dong, and Lin Liao. The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review. Frontiers in Endocrinology, Jun 2024. URL: https://doi.org/10.3389/fendo.2024.1356870, doi:10.3389/fendo.2024.1356870. This article has 12 citations.
(sun2024theclinicalcharacteristics pages 12-14): Julian Sun, Lin Ding, Liping He, Hang Fu, Rui Li, Jing Feng, Jianjun Dong, and Lin Liao. The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review. Frontiers in Endocrinology, Jun 2024. URL: https://doi.org/10.3389/fendo.2024.1356870, doi:10.3389/fendo.2024.1356870. This article has 12 citations.

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Primary Pigmented Nodular Adrenocortical Disease (PPNAD): Disease Characteristics Research Report

Executive summary (current understanding)

1. Disease information

1.1 Definition and overview

1.2 Synonyms / alternative names

1.3 Data provenance

2. Etiology

2.1 Disease causal factors

2.2 Risk factors

2.3 Protective factors

2.4 Gene–environment interactions

3. Phenotypes (clinical spectrum)

3.1 Core phenotype: ACTH-independent Cushing syndrome / hypercortisolism

3.2 Skeletal phenotype

3.3 Cardiometabolic phenotype

3.4 Pigmentary / syndromic features (Carney complex association)

3.5 Quality-of-life impact

4. Genetic / molecular information

4.1 Causal genes and inheritance

4.2 Pathogenic variants and functional classes

4.3 Genotype–phenotype association

5. Environmental information

6. Mechanism / pathophysiology

6.1 Core pathway: cAMP–PKA dysregulation (upstream → downstream causal chain)

6.2 mTORC1 activation and apoptosis resistance

6.3 KIT/SCF as a potential therapeutic axis

6.4 Wnt/cell-cycle programs downstream of PRKAR1A defects

7. Anatomical structures affected

7.1 Primary organ

7.2 Secondary system involvement (complications of hypercortisolism)

7.3 Subcellular/cellular compartments

8. Temporal development

9. Inheritance and population

9.1 Epidemiology

9.2 Demographics (from 2024 systematic review)

10. Diagnostics

10.1 Clinical and laboratory tests

10.2 Imaging

10.3 Pathology

10.4 Genetic testing strategy

10.5 Differential diagnosis

11. Outcome / prognosis

12. Treatment

12.1 Surgical (real-world implementation)

12.2 Pharmacotherapy for hypercortisolism (bridging or recurrence)

12.3 Targeted/experimental therapeutics (mechanism-informed)

12.4 Clinical trials

13. Prevention

14. Other species / natural disease

15. Model organisms

Recent developments (prioritizing 2023–2024)

Key quantitative evidence table (Sun et al., 2024)

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