Introduction
Unexplained seizures. Cardiovascular problems. Recurring kidney stones. Brain fog. Chronic fatigue. The symptoms can look very different, but for many patients they trace back to the same overlooked cause: a rare genetic disease that hasn’t yet been named.
At a recent patient event, one individual described a journey that is all too familiar: years of misdiagnosis, feeling dismissed and unheard, and eventually questioning whether the problem was real. It’s the path many people with a rare genetic disease travel before they get an answer.
One of those diseases is ADH1, or autosomal dominant hypocalcemia type 1 — a rare genetic disorder caused by mutations in the calcium-sensing receptor gene that disrupts the body’s ability to regulate calcium.
So why does diagnosis take so long? The data points to a clear answer: genetic testing — the only way to confirm an ADH1 diagnosis — is dramatically underused.
The Numbers Tell the Story
Nearly half of endocrinologists aren’t using genetic testing.
In a 2026 survey of 200 U.S. endocrinologists, 43% reported they do not order genetic testing when evaluating patients for ADH1.¹ Those physicians care for more than half (52%) of patients suspected of having the disease. That means many patients are never even given the opportunity to receive a definitive diagnosis.
Even when testing is ordered, many patients never complete it.
Approximately 1 in 3 ordered genetic tests are never completed. Common barriers include:
- Insurance or access concerns (69%)
- Uncertainty about why testing is needed (36%)
- Lack of familiarity with the testing process (28%)
- Time required to complete testing (15%)
- Distrust of genetic testing (13%)
Beyond these practical barriers, some patients hesitate for reasons that have nothing to do with logistics. Learning about a hereditary condition in the family can feel like an unwelcome burden, and some patients worry about how a genetic diagnosis might be used against them down the line.
The Genetic Information Nondiscrimination Act (GINA) protects patients from discrimination in health insurance and employment — but the law has real gaps. It doesn’t cover long-term care, disability, or life insurance. It doesn’t apply to employers with fewer than 50 employees. And it doesn’t extend to the military. Those gaps are a legitimate source of hesitation, and worth naming plainly rather than glossing over.
When all of these barriers are combined, only about one in four patients suspected of having ADH1 ultimately completes genetic testing.
The diagnosis gap doesn’t end there.
Among 152 patients studied, 70% were adults before receiving their first ADH1 diagnosis, and fewer than half see an endocrinologist, nephrologist, or geneticist in a given year — meaning most patients don’t even have a regular touchpoint with a specialist who might recognize the pattern.
Why does this matter? For a condition like ADH1, a confirmed diagnosis changes what happens next. It gives physicians a reason to look past individual symptoms — a seizure here, a kidney stone there — and treat the underlying cause instead of chasing each symptom separately. Every year that testing is delayed is a year where treatment decisions are being made without that information.
This Isn’t Just an ADH1 Problem
A 2024 survey of more than 6,500 patients living with 1,675 different rare diseases across Europe found an average of nearly five years between first symptoms and diagnosis, and that 56% of patients were diagnosed more than six months after their first medical contact.⁵ The pattern seen in many rare diseases — years lost before symptoms are connected to a genetic cause — repeats across rare disease generally.
Genetic testing itself is underused well beyond rare disease, even for conditions that share some of the same symptoms. Familial hypercholesterolemia, a genetic and treatable cardiovascular condition, is estimated to remain undiagnosed in more than 90% of the roughly 30 million people who have it worldwide, despite a genetic test being available.⁶
Even in cancer, where the value of genetic testing is well established, recent studies report that 30–48% of ordered genetic tests are never completed.²³⁴ Whatever the disease, the pattern holds: when physicians don’t order testing, or patients can’t complete it, diagnosis and treatment are delayed and opportunities to improve outcomes are missed.
What Would Close the Gap
Across these examples, the interventions that tend to move the needle share a few features: education that helps physicians and patients recognize when testing is warranted, removing cost and logistical barriers so a referral turns into a completed test, and offering testing in more places than a specialty clinic alone.
BridgeBio’s ADH1 testing program follows that pattern. It offers no-cost testing that either a provider or an eligible patient can initiate, no-cost family testing to help identify affected relatives, and flexible options — in-office, at-home, or mobile — so testing doesn’t require a specialist visit or become part of a patient’s insurance record.
Every patient who may have ADH1 deserves the opportunity to know that answer. If you care for patients with suspected ADH1 — or believe you or a family member may be affected — don’t let uncertainty stand in the way of a diagnosis.
For more informmation on genetic testing & ADH1:
Patient-initiated testing & general interest
HCP-initiated testing including at-home & mobile testing
MAT-US-ECLTX-0283 V1
Sources
1. BridgeBio-sponsored, double-blinded market research, April 2026; N=200 US endocrinologists surveyed.
2. Drogan CM, Kindler HL, Gao G, Kupfer SS. Outcomes of Universal Point-of-Care Genetic Testing in Diverse Patients With Pancreatic Ductal Adenocarcinoma. JCO Precis Oncol. 2023 Jan;7:e2200196. doi:10.1200/PO.22.00196. PMID: 36689696.
3. Falah N, Terry A, Umer A, Kastner M, Oliverio KL, Matthews N, Kelly KM, Kellar-Guenther Y. A pilot study of home-based genetic testing completion rate in telegenetics cancer clinics in West Virginia Appalachia. Am J Med Genet A. 2023 Apr;191(4):1013–1019. doi:10.1002/ajmg.a.63109. PMID: 36637370.
4. Saylor KW, Fernandes EQ, Adams M, Paraghamian S, Shalowitz DI. Predictors of germline genetic testing referral and completion in ovarian cancer patients at a Comprehensive Cancer Center. Gynecol Oncol. 2024 Jul;186:53–60. doi:10.1016/j.ygyno.2024.03.028. PMID: 38599112; PMCID: PMC11216855.
5. Faye F, Crocione C, Anido de Peña R, et al. Time to diagnosis and determinants of diagnostic delays of people living with a rare disease: results of a Rare Barometer retrospective patient survey. Eur J Hum Genet. 2024;32:1116–1126. doi:10.1038/s41431-024-01604-z. PMID: 38755315.
6. Sturm AC, Knowles JW, Gidding SS, et al. Clinical Genetic Testing for Familial Hypercholesterolemia: JACC Scientific Expert Panel. J Am Coll Cardiol. 2018;72(6):662–680. doi:10.1016/j.jacc.2018.05.044.