A Novel SCNN1B Mutation in a Neonate With Systemic Pseudohypoaldosteronism Type 1 - Case Report

Sep 30, 2026

Uploaded by Patrick

Early recognition of systemic pseudohypoaldosteronism type 1 (PHA1B) in neonates presenting with persistent hyperkalemia and hyponatremia supports timely intervention. Genetic testing establishes the diagnosis and informs long-term management decisions. This case documents a novel SCNN1B mutation, broadening the known genetic spectrum and highlighting lifelong monitoring needs. Such monitoring aims to reduce the risk of life-threatening complications.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Abstract

Introduction

Case History/Examination

Differential Diagnosis, Investigations, and Treatment

Clinical Case Reports CASE REPORT OPEN ACCESS A Novel SCNN1B Mutation in a Neonate With Systemic Pseudohypoaldosteronism Type 1: Case Report Ensiyeh Bahadoran1 | Fatemeh Saffari2 | Sahar Moghbelinejad1 1Cellular and Molecular Research Center, Research Institute for Prevention of Non-Communicable Diseases, Qazvin University of Medical Sciences, Qazvin, Iran | 2Children Growth Research Center, Research Institute for Prevention of Non-Communicable Disease, Qazvin University of Medical Sciences, Qazvin, Iran Correspondence: Sahar Moghbelinejad ([smoghbelinejad@qums.ac.ir](smoghbelinejad@qums.ac.ir)) Received: 29 January 2025 | Revised: 2 September 2025 | Accepted: 24 December 2025 Keywords: aldosterone | hyperkalemia | hyponatremia | pseudohypoaldosteronism | renin | SCNN1B gene ABSTRACT Early recognition of PHA1B in neonates with persistent hyperkalemia and hyponatremia is important for timely intervention. Genetic testing confirms the diagnosis, guiding long-term management. This case highlights a novel SCNN1B mutation, expanding the genetic spectrum and emphasizing the need for lifelong monitoring to prevent life-threatening complications. 1 | Introduction Cheek and Perry first reported pseudohypoaldosteronism type one (PHA1), a rare inherited condition, in 1958 [1] . The incidence rate of PHA1 is estimated to be approximately one in 80,000 people and is characterized by a transepithelial sodium transport deficiency [2] . Typical neonatal clinical signs of PHA1 include failure to thrive, hyponatremia, hyperkalemia, metabolic acidosis, and elevated plasma aldosterone and renin levels [3] . PHA1 can be inherited in both dominant and recessive forms. Autosomal dominant PHAI (PHA1A, renal type) is caused by mutations in the NR3C2 gene, which codes for the mineralocorticoid receptor. It is characterized by milder symptoms and salt loss that originates primarily from the kidneys. As the proximal nephron matures with age, salt loss symptoms can progressively improve [4]. Autosomal recessive PHAI (PHA1B, multisystemic type) affects one in 166,000 newborns and is distinguished by mutations in the epithelial sodium channel (ENaC) encoded by SCNN1A, SCNN1B, and SCNN1G, which encode the α, β, and γ ENaC subunits, respectively. PHA1B is a multisystemic disorder identified by significant postnatal salt wasting in the kidneys, lungs, colon, sweat, and salivary glands [2, 5] . Patients with this disorder must take salt supplements and are dependent on medical treatment for the rest oftheir lives. Some of them are also at risk of acquiring a pulmonary phenotype with frequent infections that is similar to cystic fibrosis [6] . Knowledge of this rare genetic disease has been expanded by case studies; however, the clinical presentations are variable, and the management of this case is challenging. Here, we describe the presentation, diagnosis, and treatment of a case ofsystemic pseudohypoaldosteronism type one in a neonate caused by a novel mutation in the SCNN1B gene. 2 | Case History/Examination The case was delivered vaginally at 40 weeks of gestation from a 26-year-old woman. Other than hypothyroidism, the mother had no pregnancy-related issues. During pregnancy, ultrasound and other tests showed normal results. This girl was born out of a non-consanguineous marriage and was the family's second child. The family had a girl as their first child, six years older than our case, healthy, and alive. The girl weighed 3.1 kg (36 percentile) at birth, with head circumference and length of 52 (99 percentile) and 34 cm (99 percentile), respectively. Postnatal clinical history was uneventful, and she was fed breast milk. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2026 The Author

FAQs

Why is early recognition of PHA1B important in neonates?

Early recognition is important because persistent hyperkalemia and hyponatremia require timely intervention. Genetic testing can confirm the diagnosis and guide long-term management.

How is systemic pseudohypoaldosteronism type 1 (PHA1B) diagnosed in this case?

The case uses genetic testing to reach a conclusive diagnosis of PHA1B. The patient’s clinical and laboratory findings also show markedly elevated aldosterone and renin without renal failure or adrenal insufficiency.

What differential diagnoses were considered before confirming PHA1B?

Differential diagnoses included congenital adrenal hyperplasia (CAH), Bartter syndrome, type IV renal tubular acidosis (RTA), and secondary pseudohypoaldosteronism. Normal hormonal levels, normal genitalia, no infection signs, and elevated aldosterone and renin supported PHA1B.

Sep 30, 2026

Uploaded by Patrick