An 18-day-old male infant was admitted to the hospital due to recurrent hyperkalemia for more than 10 days. The neonate had milk refusal and dyspnea. The blood gas analysis revealed recurrent hyperkalemia, hyponatremia and metabolic acidosis. Adrenocortical hormone replacement therapy was ineffective. Additional tests showed a significant increase in aldosterone levels. Family whole exome sequencing revealed that the infant had compound heterozygous in the SCNNIA gene, inherited from both parents. The infant was diagnosed with neonatal systemic pseudohypoaldosteronism type I. The infant's electrolyte levels were stabilized through treatment with sodium polystyrene sulfonate and sodium supplement. The infant was discharged upon clinical recovery. This study provides a focused description of differential diagnosis of salt-losing syndrome in infants and introduces the multidisciplinary management of neonatal systemic pseudohypoaldosteronism type I.
Infant ; Infant, Newborn ; Humans ; Male ; Pseudohypoaldosteronism/genetics* ; Hyperkalemia/etiology* ; Hyponatremia/diagnosis* ; Diagnosis, Differential

Type IV renal tubular acidosis (RTA) is due to renal tubular bicarbonate wasting associated with mineralocorticoid deficiency. In its five subtypes, IV-4 is due to pseudohypoaldosteronism (PHA) evidenced by increased plasma renin and aldosterone. PHA is believed to result from distal tubular unresponsiveness to circulating aldosterone and has normal renal and adrenal fuction. Hypoaldosteronism can easily be suspected when the patient shows typical electrolyte imbalance (hyponatremia coupled with hyperkalemia) and the diagnosis of PHA is confirmed by elevated serum aldosterone level. But some patients of PHA show negligible electrolyte imbalance, thus metabolic acidosis is a sole abnormal finding in routine laboratory examination. We experienced a case of IV-4 RTA in a 2-month-old male infant who presented with normal anion gap-metabolic acidosis as a sole abnormal finding in routine laboratory examination. RTA was suspected and the test of urine pH during systemic acidosis and fractional excretion of bicarbonate (FEHCO3-) during the condition of normal plasma bicarbonate concentration revealed the disease to be type IV RTA. With elevated plasma renin activity and aldosterone level, the diagnosis of type IV-4 RTA (pseudohypoaldosteronism) was made. Type IV RTA is the most common form of RTA, therefore it is recommended that young infants with suspected RTA should be checked for serum aldosterone level first.
Acidosis ; Acidosis, Renal Tubular* ; Aldosterone ; Diagnosis ; Humans ; Hydrogen-Ion Concentration ; Hypoaldosteronism ; Infant ; Male ; Plasma ; Pseudohypoaldosteronism ; Renin

Idiopathic renal hypouricemia is a disorder characterized by impaired urate handling in the renal tubules. This disease usually produces no symptoms, but hematuria, uric acid nephrolithiasis or acute renal failure may develop. A defect in the SLC22A12 gene, which encodes the human urate transporter, is the known major cause of this disorder. We describe a 10-month-old boy with idiopathic renal hypouricemia. He was diagnosed with transient pseudohypoaldosteronism at admission, but hypouricemia was accidentally found through follow-up study. By gene analysis, his diagnosis was confirmed to idiopathic renal hypouricemia. In addition, we report a mutation in the human urate transporter 1 (hURAT1) gene identified in his family.
Acute Kidney Injury ; Diagnosis ; Follow-Up Studies ; Hematuria ; Humans ; Infant ; Male ; Nephrolithiasis ; Pseudohypoaldosteronism ; Uric Acid

Pseudohypoaldosteronism type 1 is a genetic renal tubular disease of salt wasting, presenting in young infants. Tubular unresponsiveness to elevated endogenous and exogenous aldosterone is the suggested pathogenetic mechanism. Oral sodium chloride supplementation relieve the clinical symptoms and electrolyte distrubances. We experienced 2 cases of PHA type 1 in 38-day and 45-day old male infants who were presented with failure to thrive, vomiting and/or dehydration. Laboratory data showed hyponatremia, hyperkalemia, hypochloremia and metabolic acidosis. Renal and adrenal functions were normal. Plasma renin activity and plasma aldosterone concentration were markedly elevated. Under the diagnosis of pseudohypoaldosteronism type 1, oral supplementation of NaCl and/or kayexalate improved the clinical states of the patients.
Acidosis ; Aldosterone ; Dehydration ; Diagnosis ; Failure to Thrive ; Humans ; Hyperkalemia ; Hyponatremia ; Infant ; Male ; Plasma ; Pseudohypoaldosteronism* ; Renin ; Sodium Chloride ; Vomiting

Bartter-like syndrome encompasses a set of inherited renal tubular disorders associated with hypokalemic metabolic alkalosis, renal salt wasting, hyperreninemic hyperaldosteronism, and normal blood pressure. Antenatal Bartter syndrome, a subtype of Bartter-like syndrome, is characterized by polyhydramnios, premature delivery, life-threatening episodes of fever and dehydration during the early weeks of life, growth retardation, hypercalciuria, and early-onset nephrocalcinosis. Mutations in the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) and ATP-sensitive inwardly rectifying potassium channel (ROMK) of the thick ascending limb of Henle's loop have been identified in the antenatal Bartter syndrome. We report the identification of two heterozygous mutations of the gene for Kir 1.1 (ROMK) from an antenatal Bartter syndrome patient who presented at birth with mild salt wasting and a biochemical findings that mimicked primary peudohypoaldosteronism type 1, such as hyperkalemia and hyponatremia, and evolved to a relatively benign course. We have identified amino acid exchanges Arg338Stop and Met357Thr in the gene exon 5 for ROMK by PCR and direct sequencing. Both mutations alter the C-terminus of the ROMK protein, and can affect channel function.
Amino Acid Substitution* ; Bartter's Disease/diagnosis ; Bartter's Disease/embryology ; Bartter's Disease/genetics* ; Codon, Nonsense* ; Diagnosis, Differential ; Exons/genetics ; Female ; Heterozygote ; Human ; Infant, Newborn ; Mutation, Missense* ; Point Mutation ; Potassium Channels/chemistry ; Potassium Channels/genetics* ; Protein Conformation ; Pseudohypoaldosteronism/diagnosis