Genetic testing

ADH1 diagnosis and genetic testing confirmation

Suspect ADH1? A combination of the following can help differentiate autosomal dominant hypocalcemia type 1 (ADH1) from other forms of hypoparathyroidism and aid diagnosis:

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ADH1 is a distinct form of hypoparathyroidism

Patients with ADH1 often present with varying degrees of1,2:

  • Hypocalcemia
  • Low or inappropriately normal parathyroid hormone (PTH) relative to the degree of hypocalcemia
  • Elevated or inappropriately normal urinary calcium
  • Hyperphosphatemia
  • Hypomagnesemia

Dig deeper: Patients with ADH1 experience more pronounced hypercalciuria when treated with conventional therapy (activated vitamin D and calcium supplements).1

This is due to the combined effects of low PTH and overly sensitive calcium‑sensing receptor (CaSR) in the kidneys, leading to1,3:

  • Reduced calcium reabsorption from the kidneys
  • Associated complications:
    • Nephrocalcinosis
    • Nephrolithiasis
    • Kidney impairment
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Family history

ADH1 is inherited in an autosomal-dominant manner. A child has a 50% chance of having ADH1 if they have an affected parent.1,4

Dig deeper: Approximately 20% of ADH1 cases occur spontaneously, with no family history, so don't rule out ADH1 for patients with a medical history that is consistent with the biochemical features of ADH1.1
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Confirmatory genetic testing

Genetic testing is recommended for patients with idiopathic hypoparathyroidism.1

Best practice recommendations by panel consensus advise genetic testing in patients with idiopathic hypoparathyroidism, especially for patients5:

  • Under 40 years of age
  • With a family history of hypoparathyroidism

Benefits of testing

An accurate diagnosis informs disease management1:

  • Individualized treatment strategies
  • Patient support
    • Genetic counseling
    • Family planning
  • Patient advocacy resources

Genetic testing of the calcium‑sensing receptor gene (CASR) can help confirm a diagnosis of ADH1.1,4

BridgeBio Detect Hypopara

No-cost testing program

BridgeBio is committed to leading the way toward improved diagnosis of ADH1.

BridgeBio sponsors no-cost genetic testing and counseling programs in the United States for eligible patients and family members suspected of having genetic forms of hypoparathyroidism.

Through the partnership between PreventionGenetics and BridgeBio, the DetectHypopara program offers healthcare professionals genetic test kits at no cost for eligible patients and their family members.

For a patient to be eligible, they must reside in the United States and have 1 of the following diagnoses:

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Nonsurgical hypoparathyroidism

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Idiopathic hypoparathyroidism

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Hypocalcemia suspected to be of genetic cause

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Genetic hypoparathyroidism in a relative

Take the next step: Learn more or order a test kit

This genetic testing program leverages a whole-exome backbone using next‑generation sequencing and includes 26 genes known to cause hypoparathyroidism, including CASR, with options to collect whole blood, saliva, or buccal specimens.

The program also partners with Genome Medical to offer no-cost genetic counseling to support healthcare professionals in helping their patients understand their genetic test results and identifying family members who may also be affected.

Order no-cost genetic test Detect HypoPara program

NOTE: Kits are provided at no cost and include prepaid return postage. Kits may take up to 1 week for delivery.

References: 1. Roszko KL, Stapleton Smith LM, Sridhar AV, et al. Autosomal dominant hypocalcemia type 1: a systematic review. J Bone Miner Res. 2022;37(10):1926-1935. 2. Pearce SH, Williamson C, Kifor O, et al. A familial syndrome of hypocalcemia with hypercalciuria due to mutations in the calcium‑sensing receptor. N Engl J Med. 1996;335(15):1115-1122. 3. Roszko KL, Bi RD, Mannstadt M. Autosomal dominant hypocalcemia (hypoparathyroidism) types 1 and 2. Front Physiol. 2016;7:458. 4. Bilezikian JP, Khan A, Potts JT Jr, et al. Hypoparathyroidism in the adult: epidemiology, diagnosis, pathophysiology, target-organ involvement, treatment, and challenges for future research. J Bone Miner Res. 2011;26(10):2317-2337. 5. Khan AA, Ali DS, Bilezikian JP, et al. Best practice recommendations for the diagnosis and management of hypoparathyroidism. Metabolism. 2025;171:156335.