Everyone Healthy Library
Multiple Endocrine Neoplasia Type IIA
Condition / disease reference page from the Everyone Healthy database.
Connected health information
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Condition overview
Attributes
Commonalityis rare
Linked signs and symptoms
0No related signs or symptoms are listed yet.
Linked drugs / medications
0No linked drugs are listed yet.
Treatments, therapies and supportive options
0Grouped by treatment type. These are educational database links, not personal treatment recommendations. Evidence labels are shown only where stored in the EH database.
No linked treatment or supportive options are listed yet.
Linked diagnostic tests and investigations
5These are pulled from both EH diagnostic-test link tables, including the older large test-link table.
Biological and test markers
5This visual map uses existing EH database links to show biological agents and lab markers reported as increased, decreased, or associated with this condition. These are educational relationships only; test results must be interpreted by a qualified clinician because ranges vary by lab, method, age, sex and clinical context.
Often decreased
4- Folic Acid (Folate)Reference range exampleInfant (0 - 1y): 14–51 ng/mL; Child (0 - 16y): 5–21 ng/mLLinked diagnostic tests1Folic Acid (Folate) Concentration
- Hemoglobin (Hb)Reference range exampleFemale: 78–100 gm/dL; Male: 76–100 gm/dLLinked diagnostic tests3Hemoglobin (Hb) Concentration, Mean Corpuscular Hemoglobin (MCH) Weight Test
- IronReference range exampleChild (0 - 16y): 50–120 µg/dL; Adult ( > 16y), Female: 50–150 µg/dLLinked diagnostic tests2Iron Concentration, Total Iron Binding Capacity (TIBC)
- Low Density Lipoprotein (LDL)Reference range exampleAdult ( > 16y): 0–125 mg/dL; 6y - 16y: 0–100 mg/dLLinked diagnostic tests1Low Density Lipoprotein (LDL) Concentration
Other associated markers
0No markers in this group.
Introduction / full article
Multiple Endocrine Neoplasia Type IIA
Multiple endocrine neoplasia type IIA
Multiple endocrine neoplasia type 2A, also called Sipple's syndrome, is a group of medical disorders associated with tumors of the endocrine system. The tumors may be benign or malignant (cancer). They generally occur in endocrine organs (e.g. thyroid, parathyroid, and adrenals), but may also occur in endocrine tissues not in a classical endocrine organ. MEN2A is a sub-type of MEN (multiple endocrine neoplasia).
Classification
Before gene testing was available, the type and location of tumors determined which type of MEN2 a person had. Gene testing now allows a diagnosis before tumors or symptoms develop.
A table in the multiple endocrine neoplasia article compares the various MEN syndromes. MEN2 and MEN1 are distinct conditions, despite their similar names. MEN2 includes MEN2A, MEN2B, and familial medullary thyroid cancer.
The common feature among the three sub-types of MEN2 is a high propensity to develop medullary thyroid carcinoma.
Presentation
MEN2 can present with a sign or symptom related to a tumor or, in the case of multiple endocrine neoplasia type 2b, with characteristic musculoskeletal and/or lip and/or gastrointestinal findings.
Causes
The table in the multiple endocrine neoplasia article lists the genes involved in the various MEN syndromes. Most cases of MEN2A derive from a variation in the RET proto-oncogene, and are specific for cells of neural crest origin.
The protein produced by the RET gene plays an important role in the TGF-beta (transforming growth factor beta) signaling system. Because the TGF-beta system operates in numerous tissues throughout the body, variations in the RET gene can have effects in numerous tissues throughout the body.
MEN2A generally results from a gain-of-function variant of a RET gene. Other diseases, such as Hirschsprung disease, result from loss-of-function variants. OMIM #164761 lists the syndromes associated with the RET gene.
Genetics
When inherited, multiple endocrine neoplasia type 2A is transmitted in an autosomal dominant pattern, which means affected people have one affected parent, and possibly-affected siblings and children. Some cases, however, result from spontaneous new mutations in the RET gene. These cases occur in people with no family history of the disorder. In MEN2B, for example, about half of all cases arise as spontaneous new mutations.
Differences in presentation
As noted, all types of MEN2 include pheochromocytoma, and medullary thyroid carcinoma.
MEN2A is additionally characterized by the presence of parathyroid hyperplasia or tumor.