Diagnostic and management considerations in pseudohypoaldosteronism type 1b

Pseudohypoaldosteronism type 1B is a rare autosomal recessive disorder caused by dysfunction of amiloride-sensitive epithelial sodium channels (ENaCs). We present the case of a neonate with cardiogenic shock after cardiac arrest due to profound hyperkalaemia. Genetic testing revealed a novel homozygous variant in SCNNIA. We review diagnostic considerations including the molecular mechanisms of disease, discuss treatment approaches and highlight the possible significance of the diversity of pulmonary ENaCs.

A Neonate with Autosomal Dominant Pseudohypoaldosteronism Type 1 Due to a Novel Microdeletion of the NR3C2 Gene at 4q31.23

Dehydration with hyponatremia can occur from a variety of causes and can be potentially fatal to infants. Pseudohypoaldosteronism type 1 (PHA1) is a rare disease that can cause severe dehydration along with hyponatremia and hyperkalemia because of renal tubular unresponsiveness to mineralocorticoids. Autosomal dominant PHA1 (ADPHA1, OMIM #177735) is caused by inactivating mutations in the NR3C2 gene, which encodes the mineralocorticoid receptor, and it can lead to renal salt-wasting, dehydration, and failure to thrive during infancy. Here, we report a case of a 20-day-old female neonate who presented as severe dehydration with hyponatremia and polyuria. We suspected that her diagnosis might be PHA1 based on markedly elevated plasma renin activity and serum aldosterone levels. For the genetic diagnosis of PHA1, we performed targeted exome sequencing of all causative genes of PHA1, but the result was negative. We confirmed by chromosomal microarray that a novel heterozygous microdeletion was found in the 4q31.23 region spanning exons 7–9 of the NR3C2 gene, and the patient was diagnosed with ADPHA1. In conclusion, our patient is a case of ADPHA1 that developed into a salt-wasting crisis in the neonatal period due to a microdeletion of the 4q31.23 region inherited from her father.

A late diagnosis of Pseudohypoaldosteronism type I in an infant with hypoplastic left heart syndrome presenting with failure to thrive

Pseudohypoaldosteronism type I is caused by a peripheral resistance to aldosterone and can present with electrolyte abnormalities, poor growth, or dehydration. Although a rare disease, several case reports have been published regarding Pseudohypoaldosteronism type I in neonates and infants. We report a case of failure to thrive and hyponatremia in an infant with hypoplastic left heart syndrome who was subsequently found to have Pseudohypoaldosteronism type I.

Novel SCNN1A gene splicing-site mutation causing autosomal recessive pseudohypoaldosteronism type 1 (PHA1) in two Italian patients belonging to the same small town

Introduction Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease due to the peripheral resistance to aldosterone. Its clinical spectrum includes neonatal salt loss syndrome with hyponatremia and hypochloraemia, hyperkalemia, metabolic acidosis and increased plasmatic levels of aldosterone. Two genetically distinct forms of disease, renal and systemic, have been described, showing a wide clinical expressivity. Mutations in the genes encoding for the subunits of the epithelial sodium channels (ENaC) are responsible for generalized PHA1. Patients’ presentation We hereby report on two Italian patients with generalized PHA1, coming from the same small town in the center of Sicily. The first patient is a male child, born from the first pregnancy of healthy consanguineous Sicilian parents. A novel SCNN1A (sodium channel epithelial subunit alpha) gene mutation, inherited from both heterozygous parents, was identified by next generation sequencing (NGS) in the homozygous child (and later, also in the heterozygous maternal aunt). A more detailed family history disclosed a possible related twenty-year-old girl, belonging to the same Sicilian small town, with referred neonatal salt loss syndrome associated to hyperkalemia, and subsequent normal growth and neurodevelopment. This second patient had a PHA1 clinical diagnosis when she was about 1 year old. The genetic investigation was, then, extended to her and to her family, revealing the same mutation in the homozygous girl and in the heterozygous parents. Conclusions The neonatologist should consider PHA1 diagnosis in newborns showing hyponatremia, hyperkalemia and metabolic acidosis, after the exclusion of a salting-loss form of adrenogenital syndrome. The increased plasmatic levels of aldosterone and aldosterone/renin ratio, associated to a poor response to steroid administration, confirmed the diagnosis in the first present patient. An accurate family history may be decisive to identify the clinical picture. A multidisciplinary approach and close follow-up evaluations are requested, in view of optimal management, adequate growth and development of patients. Next generation sequencing (NGS) techniques allowed the identification of the SCNN1A gene mutation either in both patients or in other heterozygous family members, enabling also primary prevention of disease. Our report may broaden the knowledge of the genetic and molecular bases of PHA1, improving its clinical characterization and providing useful indications for the treatment of patients. Clinical approach must be personalized, also in relation to long-term survival and potential multiorgan complications.

Systemic pseudohypoaldosteronism-1 with episodic dyslipidemia in a Sudanese child

Summary Systemic pseudohypoaldosteronism type 1 (PHA1) is a rare genetic syndrome of tissue unresponsiveness to aldosterone caused by mutations affecting the epithelial Na channel (ENaC). The classical presentation is life-threatening neonatal/infantile salt-losing crises that mimic congenital adrenal hyperplasia (CAH). Consistently, extra-renal manifestations, including respiratory symptoms that resemble cystic fibrosis, are well reported. Clinical diagnosis is made by the presence of hyponatremia, hyperkalemia, metabolic acidosis, respiratory symptoms, evidence of high renal and extra-renal salt loss in addition to high plasma renin and aldosterone levels. We herein report a novel manifestation of PHA1: episodic dyslipidemia in a 7-month-old Sudanese boy that occurred during the salt-losing crises. Whole exome sequencing of the patient revealed one homozygous missense variant c.1636G>A p.(Asp546Asn) in the SCNN1B gene, confirming our clinical and laboratory findings that were compatible with PHA1. This report aims to highlight the possible explanation of dyslipidemia in PHA1 and its expected consequences in the long term. Learning points A child presenting with features that mimic salt-losing congenital adrenal hyperplasia (CAH) crises that do not respond to glucocorticoid and mineralocorticoid therapy should alert the pediatricians to the possibility of end-organ resistance to aldosterone. Pseudohypoaldosteronism type 1 (PHA1) can be diagnosed even in the absence of advanced laboratory investigations. To our knowledge, this is the first case of systemic PHA1 to have a documented episodic dyslipidemia (primarily as marked hypertriglyceridemia).

A case report of pseudohypoaldosteronism type II with a homozygous KLHL3 variant accompanied by hyperthyroidism

Background Pseudohypoaldosteronism type II (PHAII), also called Gordon syndrome, is a rare hereditary disease caused by variants in the WNK1, WNK4, KLHL3 and CUL3 genes. The combination of PHAII with hyperthyroidism and secondary hyperparathyroidism has not been reported previously. Case presentation A 54-year-old female with recently diagnosed Graves’ disease presented hyperkalemia, hypertension, hypercalciuria, elevated levels of parathyroid hormone (PTH) and normal renal function. PHAII was established based on the finding of a homozygous variant (c.328 A > G, T110A) in the KLHL3 gene. Low-dose thiazide diuretics normalized her potassium, calcium and PTH. Conclusions PHAII caused by a KLHL3 variant can affect adults later in life. This diagnosis should be considered in patients with hypertension, consistent hyperkalemia, and normal eGFR and can be corrected by thiazides. The patient also had hyperthyroidism and secondary hyperparathyroidism. The latter was also corrected by thiazide treatment. The hyperthyroidism was assumed to be unrelated to PHAII.

A unique genotype of pseudohypoaldosteronism type 1b in a highly consanguineous population

Context This study describes the molecular genetics of pseudohypoaldosteronism type 1b (PHA 1b) in the highly consanguineous population of two Arabian Gulf countries, Saudi Arabia and Oman. Patients and Methods This study enrolled 22 patients from 13 unrelated families (two families with five patients from Oman and 11 families with 17 patients from Saudi Arabia). All of these patients had presented within the first 10 days of life with nausea and vomiting, hyponatremia, hyperkalemia and hypotension. We isolated DNA from peripheral blood and PCR-sequenced all exons and exon-intron boundaries of SCNN1A and, if negative, SCNN1B and SCNN1G using the Dideoxy Chain termination method. Results We found a total of eight mutations in 13 families as follows: six mutations in SCNN1A, one in SCNN1B, and one in SCNN1G. All of these mutations were novel except one. SCNN1A mutations were: c.1496A>G, p.Q499R (novel) in one patient; c.1453C>T, p.Q485X (novel) in one patient; c.1322_1322delA, p.N441Tfs*41 (novel) in two patients of one family; c.876 + 2 delGAGT (novel) in three patients of one family; c.203_204 delTC, p.I68Tfs*76 (known mutation) in eight patients of five families; and whole SCNN1A gene deletion (novel) in two patients of two families. In addition, a nonsense SCNN1B mutation c.1694C>A, p.S565X (novel) was found in three siblings from one Omani family, and an SCNN1G deletion mutation c.527_528 delCA, p.T176Rfs*9 (novel) in two siblings form another Omani family. Conclusion We characterized a unique genotype of PHA 1b with several novel gene-structure disrupting mutations in SCNN1A, SCNN1B and SCNN1G in a consanguineous population.

A Rare Case of Pseudohypoaldosteronism Type II or Gordon Syndrome

Introduction: Pseudohypoaldosteronism type II (PHA II) or Gordon Syndrome is a rare, autosomally inherited disease with unknown prevalence. It is caused by mutations in the WNK1, WNK4, CUL3, or KLHL3 gene. It is characterized by hypertension, hyperkalemia, hyperchloremic metabolic acidosis and low plasma aldosterone levels, but otherwise normal kidney function. The age of onset of PHA2 is variable, ranging from infancy or childhood to adolescence and adultdood. The electrolyte and blood pressure abnormalities of PHA II is often managed with salt restriction and hydrochlorthiazide (HCTZ). Here we report a rare case of Pseudohypoaldosteronism type II in an adolescent patient. Case Presentation: A 16-yo female with past medical history of asthma and anemia presented to the emergency department with acute severe abdominal/suprapubic pain, associated with diaphoresis, non bloody diarrhea and non bilious non bloody vomiting. The patient also reported daily headaches relieved with Tylenol. In the ED, she was found to be hypertensive at 190/118 mmHg. Blood count showed mild anemia but normal white count and platelets. Comprehensive metabolic panel showed sodium 140, potassium 6.6, chloride 115, bicarbonate 16, creatinine 0.5, and normal liver enzymes. Urine electrolytes were as follows: sodium 189, potassium 20.8 and chloride 140. Arterial Blood Gas ahowed pH of 7.32. Plasma renin activity was low normal at 0.34 and aldosterone level was 2. CT scan of abdomen and pelvis was unremarkable. The blood work was consistent with pseudohypoaldosteronism type II or Gordon syndrome. The patient was adopted so there was no family history. She was started on hydrochlorothiazide. Later, she developed severe itching reaction with hydrochlorthiazide. She is currently being treated with Indapamide, with well controlled blood pressure and normal electrolytes. Conclusion: Pseudohypoaldosteronism type II or Gordon’s Syndrome is a rare disease, with usually autosomal dominant inheritance, with no specific diagnostic criteria for diagnosis. It should be suspected in adolescent or adult patients with hyperkalemia with normal glomerular filtartion, accompanied by hypertension (can be absent), metabolic acidosis, hyperchloremia, decreased plasma renin, relatively suppressed aldosteronism and family history of similar findings.

Hypercalcemia in an Infant With Pseudohypoaldosteronism Type 1

Background: Pseudohypoaldosteronism type 1 (PHA1) is an aldosterone resistance syndrome due to insensitivity of target tissues to aldosterone action, with supraphysiologic aldosterone and renin levels. PHA1 presents usually in infancy and is divided into autosomal dominant (AD) and autosomal recessive (AR) form. A secondary form of PHA1 associated with UTI and/or renal malformations was described. In AD PHA1, salt loss is due to renal mineralocorticoid resistance while hyponatremia in AR PHA1 is caused by multi-organ salt loss. PHA1 has variable signs/symptoms associated with hyponatremia and hyperkalemia; thus, this clinical picture can be attributed to more common conditions such as dehydration, poor feeding, congenital adrenal hyperplasia. Clinical Case: A 5-month old male was admitted for airway evaluation. He was a 23-week gestation preemie, with chronic lung disease, failure to thrive. Patient was found to have hyponatremia, hyperkalemia, high FeNa of 1.3% (intrinsic renal disease) and elevated BUN/Cr (92/1.15). Renal US found echogenic kidneys with poor cortical medullary differentiation suggesting renal disease. Further evaluation noted high aldosterone (1700 ng/dL) and renin (400 ng/mL/hr) levels. He was placed on low protein formula to help optimize BUN level. Baby was diagnosed with secondary PHA1 due to renal disease and started on NaCl supplementation. This led to normalization of BUN, creatinine and improvement in electrolytes. Patient also had high serum calcium ranging from 11.1 to 12.0 mg/dL. Hyponatremia, hyperkalemia, hypercalcemia could be attributed to possible CAH, however state screen and ACTH stimulation test were normal. Further workup showed high 25-OH-vitamin D > 99 ng/mL, PTH 46.9 pg/mL, phosphorous 5.4 mg/dL and 1,25-OH-vitamin D 63.1 pg/mL. Urine Ca/cr ratio was 0.522. Vitamin D supplementation was stopped and daily total fluids increased. Subsequently, there was improvement in serum Ca at 10.9 mg/dL and 25-OH Vitamin D of 74 pg/mL. Next Generation Sequencing (NGS) was carried out, with a focus on the etiology of persisting hypercalcemia, including familial forms of hypercalcemia and Williams Syndrome. NGS revealed a likely pathogenic variant, c.2365 + 2T>C (p.?), in NR3C2, consistent with a diagnosis of AD PHA 1. Conclusion: This is a case of AD PHA1, marked by renal mineralocorticoid receptor resistance associated with persisting hypercalcemia. Initial hypercalcemia could be explained by hypervitaminosis D. It is important to note that electrolyte abnormalities, including persistent hypercalcemia, could be also secondary to the kidney disease found on renal US. There are only few reports of hypercalcemia in patients with PHA1 in the literature. In children with electrolyte abnormalities and failure to thrive, monitoring of serum and urine electrolytes would facilitate early accurate diagnosis and timely treatment.