Diagnostic pitfalls in aldosterone defects: a 9-year follow-up of early-onset pseudohypoaldosteronism type 2.

OBJECTIVES

Pseudohypoaldosteronism type 2 (PHA2) is a rare autosomal dominant electrolyte disorder characterized by hypertension, hyperkalemia, metabolic acidosis, and suppressed renin activity, usually with preserved renal function. Pathogenic variants in WNK1, WNK4, KLHL3, and CUL3 have been identified, with CUL3 mutations particularly associated with early-onset and severe phenotypes. Thiazide diuretics are effective in correcting both electrolyte imbalance and hypertension.

CASE PRESENTATION: We report a pediatric patient with early-onset PHA2 caused by a de novo splice-site variant (c.1207-2A>C) in the CUL3 gene. The patient, first evaluated at 2 years and 7 months of age for recurrent vomiting, was found to have hyponatremia, hyperkalemia, and metabolic acidosis, initially treated with fludrocortisone. On referral, significant hypertension, hyperkalemia, and suppressed renin and aldosterone were observed. Initiation of low-dose thiazide therapy led to normalization of blood pressure and electrolytes. Long-term follow-up confirmed clinical stability, normal growth, and appropriate developmental milestones.

CONCLUSIONS

Aldosterone pathway defects may be misdiagnosed during the initial clinical assessment. This underscores the importance of a comprehensive diagnostic approach incorporating biochemical profiling and genetic testing to ensure accurate identification. Next-generation sequencing has emerged as a valuable tool for establishing a definitive diagnosis, particularly in cases with aldosterone defects. Timely and accurate diagnosis of PHA2 is critical, as persistent metabolic acidosis and hypertension may lead to significant growth and developmental impairments in pediatric patients. Despite the potential severity of clinical manifestations associated with CUL3-related PHA2, it is noteworthy that treatment with thiazide diuretics alone can effectively restore electrolyte balance and support normal growth and development.