Neonatal severe hyperparathyroidism

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Neonatal severe primary hyperparathyroidism (NSHPT) is characterized by severe hypercalcemia (> 3.5 mM) from birth and associated with major hyperparathyroidism.

The prevalence is unknown.

The clinical manifestations are early (with onset occurring during the first days of life) and severe, including respiratory distress due to hypotonia and rib cage deformities, bone under mineralization, and multiple fractures, all of which influence the immediate vital prognosis.

NSHPT is associated in most cases with homozygous inactivating mutations in the CASR gene, localized to 3q21.1. This gene encodes the calcium-sensing receptor (CaSR), a member of the subfamily of G protein-coupled transmembrane receptors. CaSR plays a key role in the regulation of phosphocalcic metabolism by controlling parathyroid hormone (PTH) secretion and calcium urinary excretion in response to variations in serum calcium levels.

Biologically, children present with extremely high serum calcium and serum PTH levels and a relative hypocalciuria, but in some cases they present with a markedly elevated calciuria.

'Familial hypocalciuric hypercalcemia (FHH; see this term) is a differential diagnosis. Hypercalcemia is usually milder and PTH levels are lower in FHH than in NSHPT and FHH is asymptomatic in most cases.'

Prenatal diagnosis might be proposed to parents if they are both suffering from FHH.

NSHPT represents the homozygous form of FHH and is transmitted as an autosomal recessive trait. However, sporadic forms of NSHPT occur and are associated with a heterozygous de novo mutation in the CASR gene. To date, there have been no reports of severe neonatal hyperparathyroidism with homozygous mutations in those with FHH type 2 or 3 (see these terms) but their molecular identification is still too recent to make any definite conclusions.

The control of hypercalcemia is often obtained through progressive therapeutic intervention involving the use of bisphosphonates, dialysis or even calcimimetics. If this is unsuccessful, a total parathyroidectomy is required. After parathyroidectomy, life-long treatment with 1-alpha hydoxylated vitamin D is required.

Patients can die from complications of hypercalcemia during the neonatal period from respiratory distress and dramatic hypercalcemia.

Visit the Orphanet disease page for more resources.

Last updated: 5/16/2014

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

• Cinacalcet (Brand name: Sensipar®) - Manufactured by Amgen, Inc.
  FDA-approved indication: Treatment of hypercalcemia in adult patients with primary hyperparathyroidism for whom parathyroidectomy would be indicated on the basis of serum calcium levels, but who are unable to undergo parathyroidectomy.
  National Library of Medicine Drug Information Portal
  Medline Plus Health Information

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.