Abstract: SA-PO0656
Bartter Syndrome in a Heterozygous Carrier with Electrolyte-Wasting Tubulopathy
Session Information
- Monogenic Kidney Diseases: Tubular and Other
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases
Authors
- Choi, Esther, University of California Irvine School of Medicine, Irvine, California, United States
- Kharabaf, Sohrab, University of California Irvine School of Medicine, Irvine, California, United States
- Gee, Caroline A, University of California Irvine School of Medicine, Irvine, California, United States
- Le, Dao, UCI Health, Orange, California, United States
- Nguyen, Matthew Duy Thanh Luyen, University of California Irvine School of Medicine, Irvine, California, United States
- Hanna, Ramy Magdy, UCI Health, Orange, California, United States
Introduction
Bartter syndrome (BS) is a rare autosomal recessive renal tubulopathy characterized by hypokalemia, metabolic alkalosis, and elevated renin and aldosterone levels in the absence of hypertension. It is classically associated with mutations affecting sodium, potassium, and chloride transport in the thick ascending limb of the loop of Henle. Heterozygous carriers are generally considered asymptomatic however, certain clinical contexts may unmask subclinical defects in electrolyte handling.
Case Description
We present a 60-year-old Hispanic female with a complex medical history including Graves’ disease, multiple small bowel resections, and chronic constipation. She presented with complaints of fatigue, palpitations, and intermittent muscle cramps. Laboratory evaluation revealed persistent hypokalemia (2.8 mmol/L) and hypomagnesemia (1.6 mg/dL). Her thyroid function was optimized, and proton pump inhibitors were discontinued due to concern for iatrogenic magnesium wasting, yet her electrolyte abnormalities persisted. A nephrology workup showed mildly elevated fractional excretion of magnesium (2.4%) and borderline potassium wasting without significant diuretic use. Genetic testing later revealed a heterozygous variant in a gene associated with Bartter syndrome. With oral and intravenous electrolyte supplementation her serum potassium and magnesium levels normalized and her symptoms improved.
Discussion
This case highlights the possibility that heterozygous carriers of BS-related mutations may manifest clinically significant symptoms under certain physiological or pathological conditions such as thyroid dysfunction or intestinal malabsorption. Although BS is typically diagnosed in homozygous individuals with early-onset symptoms, this case expands the spectrum of disease expression and raises awareness that carrier status may not always be entirely benign. Clinicians should maintain a high index of suspicion for renal tubular disorders in patients with persistent electrolyte abnormalities, even when genetic findings suggest only carrier status.