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Abstract: PO2312

Severe Hyperkalemia in a 4-Month-Old Female due to Cullin-3 Mutation

Session Information

Category: Trainee Case Report

  • 1700 Pediatric Nephrology

Authors

  • Yu, Grace C., Baylor Scott and White Central Texas, Temple, Texas, United States
  • Hashim, Faris Q., Baylor Scott and White Central Texas, Temple, Texas, United States
  • Hanna, Christian, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Introduction

Pseudohypoaldosteronism (PHA) type II, also known as familial hyperkalemic hypertension, is a rare autosomal-dominant disorder that causes renal tubular acidosis (RTA) type 4, characterized by late-onset hypertension, hyperkalemia, non-gap metabolic acidosis, and low or low-normal plasma renin and aldosterone levels. We present a case of a female infant with PHA type II who presented with asymptomatic severe hyperkalemia due to Cullin-3 Mutation. Treatment with thiazide diuretics resulted in rapid correction of her hyperkalemia.

Case Description

A 4-month-old former term female with an unremarkable past medical history presented for management of right neck abscess. Family history was significant for an unspecified seizure and movement disorder in her older sister. She had appropriate growth for her age, with weight, length, and head circumference all measuring around the 20th percentile. Vital signs including blood pressure were normal. Admission laboratories revealed high potassium level of 8.4 mEq/L, low bicarbonate level of 10 mEq/L (normal for age is 19–24), high chloride level of 116 mEq/L (normal for age is 97–108). Anion gap was normal at 10 mEq/L. No electrocardiogram changes were noted. Additional studies revealed positive urine anion gap of 40 mEq/L, a normal serum aldosterone level of 22 ng/L and a low renin activity of 0.2 ng/ml/hr (normal for age is 2–37). She received intravenous calcium gluconate, sodium acetate, and sodium polystyrene sulfonate for hyperkalemia management. Whole exome sequencing revealed a de novo heterozygous c.1376A>T (p.K459M) mutation in the Cullin 3 (CUL3) gene consistent with PHA type II. She was treated with thiazide diuretics, which quickly corrected her metabolic abnormalities.

Discussion

Our case of PHA type II with a CUL3 pathogenic variant is exceptionally rare, especially given the patient’s age at presentation and the negative family history. Her diagnosis could have been easily missed were she not hospitalized for her neck abscess. Without genetic evaluation and prompt thiazide diuretic treatment, she may have eventually suffered from failure to thrive and hypertension at a later point in life because of chronic hyperkalemia and metabolic acidosis. Primary care physicians and nephrologists should consider the possibility of PHA type II in any child who presents with hyperkalemia and metabolic acidosis with or without hypertension.