Rare Diseases in Endocrinology
Although several endocrine system disorders—such as diabetes, thyroid disease, and osteoporosis—are among the most common and wellknown medical conditions, some patients who have been referred to an endocrinologist will require treatment for a rare disease. Many of these rare diseases are severe and lead to myriad sequelae and secondary diseases.
According to the National Institutes of Health, more than 175 distinct rare diseases affect the endocrine system, a complex system of organs and glands that employs about 30 different hormones to influence a spectrum of vital functions including growth, metabolism, heart function, and fertility. Among these diseases are gland-based hormonal imbalances resulting in developmental abnormalities and associated complications (eg, acromegaly, gigantism, Prader-Willi syndrome), weight regulation issues and physical abnormalities (eg, Addison’s disease, Cushing’s disease), autoimmune conditions (eg, Graves’ disease), neurological diseases (eg, fragile X syndrome), blood diseases (eg, sickle-cell disease, beta thalassemia), and numerous carcinogenic and noncarcinogenic endocrine-related tumor disorders (eg, neuroendocrine cancer, multiple endocrine neoplasia, adrenocortical carcinoma, papillary thyroid carcinoma, primary thyroid lymphoma). Rare endocrine diseases can potentially impact any organ system, however.
Due to the complex and generalized nature of rare endocrine disorders, they can prove a great challenge to properly diagnose. Sometimes, disease presentation can be subtle, slow, and relatively inconspicuous; other conditions go undetected and/or are misdiagnosed because they so closely mimic, in presentation and early-stage symptomatology, other disease states. For example, a child who complains of recurrent, bilateral lower extremity pain is, more than likely, experiencing a normal stage in their development process (colloquially known as “growing pains”).
However, in rare cases, an identical symptom profile might indicate the onset of a severe and devastating endocrine disease. If a given condition is not detected at an early stage, difficulties can intensify. Clinicians can struggle to find root causes and core pathology as the rare endocrine disorder may begin to affect various body systems.
Early diagnosis, in this disease class especially, often has a tremendous influence on treatment outcomes and, at least in some instances, can be characterized as having life-or-death importance.
Optimal disease management involves a coordinated, multidisciplinary, team-oriented approach among practitioners of all relevant specialties. Time and again, research has demonstrated that multidisciplinary care is linked to diagnostic improvements.
Endocrinology diagnostic tests and procedures:
Facts and figures:
List of rare conditions:
FDA-approved orphan drugs:
Because most endocrine disorders stem from the over- or underproduction of a given hormone, treatment strategies focus on correcting these hormonal imbalances. Excess hormonal output is
treated via radiation therapy, surgery, and/or hormone suppression drugs, and sometimes receptor antagonists. Hormonal deficiency is occasionally treated with drugs that stimulate hormone production; however, the most common treatment is hormone replacement therapy with synthetic hormones. In cases with tumor involvement, whether nonmalignant or malignant, surgery and/or radiation therapy may be the path chosen.
Below are a few of the orphan drug therapies approved to treat rare endocrine disorders. Among the most recent examples are:
parathyroid hormone (branded Natpara), for the control of hypocalcemia in patients with hypoparathyroidism, approved in January 2015
pasireotide (marketed as Signifor) for the treatment of acromegaly, approved in December 2014
Somavert (pegvisomant) and Sandostatin (octreotide acetate) for acromegaly
Signifor (pasireotide) for Cushing’s disease
Droxia (hydroxyurea) for sickle cell anemia
Taxol (paclitaxel) for pancreatic cancerensipar (cinacalcet) for parathyroid carcinoma
Numerous ongoing clinical trials designed to develop the next generation of orphan drug treatment for rare endocrine disorders are currently underway. A sampling of late-stage research, all in phase 3, includes studies of:
Addison’s disease (dehydroepiandrosterone; hydrocortisone; tetracosactide)
Neuroendocrine tumors (pasireotide)
Sickle cell disease (poloxamer 188; rivipansel)
Zollinger-Ellison syndrome (YF476)
Advocacy Support and Information
Rare-disease advocacy groups provide a wealth of resources and a strong support network for patients and caregivers. See Appendix B of this resource guide for a comprehensive list of rare disease advocacy groups. Below is a sampling of advocacy groups that patients, families, and clinicians can access for information about rare endocrine-related diseases:
Society for Endocrinology:
Acromegaly Community, Inc:
National Adrenal Diseases Foundation:
Rare Cancer Research Foundation:
Cushing Support & Research Foundation:
National Fragile X Foundation:
Pancreatic Cancer Action Network:
Prader-Willi Syndrome Association: