Abstract: PUB281
Suspected Hepatocyte Nuclear Factor 1-beta (HNF1B) Glomerulocystic Kidney Disease: A Case Report of Recurrent Hypomagnesemia and Kidney Cysts in a 30-Year-Old Woman
Session Information
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Cystic
Authors
- Hashmi, Syed Salman Hamid, Staten Island University Hospital, Staten Island, New York, United States
- Bonifant, George C., Staten Island University Hospital, Staten Island, New York, United States
Introduction
Hepatocyte Nuclear Factor 1-beta (HNF1B) glomerulocystic kidney disease (GCKD) is a rare genetic disorder characterized by renal cysts, renal dysfunction, and extrarenal manifestations like hypomagnesemia, diabetes, and liver abnormalities. This case report presents a 30-year-old female with polycystic kidney disease (PCKD) and chronic hypomagnesemia, whose clinical presentation raises the suspicion of HNF1B GCKD.
Case Description
A 30-year-old female with a history of polycystic kidney disease (PCKD), transaminitis, chronic hypomagnesemia, and recurrent urinary tract infections presented with abdominal pain, nausea, and vomiting. These symptoms typically coincided with low magnesium levels. Her vital signs were stable. Laboratory tests revealed a magnesium level of 0.8 mg/dL. A CT scan showed multiple cortical and parapelvic cysts in both kidneys and multiple kidney stones over 6 mm. Urinalysis indicated small leukocyte esterase. Despite taking 2 grams of magnesium daily, her levels remained low, suggesting a genetic cause. Urinary fractional excretion of magnesium was elevated. The presence of renal cysts, hypomagnesemia, bicornuate uterus, kidney stones, and transaminitis suggested a potential diagnosis of HNF1B-related genetic kidney cystic disease (GCKD). She was discharged with high-dose oral magnesium lactate, amiloride, and is receiving weekly magnesium infusions. She was referred for genetic testing for HNF1B mutations and the results are pending.
Discussion
HNF1B GCKD is often underdiagnosed due to its phenotypic variability. The diagnosis is considered in patients with renal cysts and systemic features like hypomagnesemia and hyperglycemia. This patient's recurrent hypomagnesemia despite supplementation, transaminitis, renal cysts, and bicornuate uterus align with HNF1B GCKD. Management focuses on symptom relief, electrolyte balance, and renal function monitoring. Magnesium supplementation is crucial, and genetic testing is recommended. Amiloride blocks ENaC channels in the distal nephron, creating an electrical gradient favoring magnesium absorption via transient receptor potential melastatin channels. This case underscores the importance of considering HNF1B GCKD in patients with PCKD and chronic hypomagnesemia.