A novel homozygous CLCNKB variant: An early presentation of classic Bartter syndrome in a neonate

• Published in: Birth defects research 2023-10, Vol.115 (17), p.1674-1679
• Main Authors: Yaprak, Deniz, Kara, Hüdaverdi, Calisici, Erhan, Karagöl, Belma Saygılı, Altan, Mustafa
• Format: Article
• Language: English
• Subjects: Abnormalities; Aldosterone; Alkalosis; Bartter's syndrome; Biochemistry; Birth weight; Calcium; Cesarean section; Creatine; Dehydration; Diagnosis; Electrolytes; Emergency medical services; Endocrine disorders; Excretion; Fetuses; Genetic screening; Health services; Homeostasis; Hypercalciuria; Hypocalcemia; Indomethacin; Jaundice; Kidneys; Metabolism; Mutation; Neonates; Patients; Pediatrics; Polyuria; Renin; Salt; Salts; Seizures; Sodium; Urine; Weight loss
• ISSN: 2472-1727; 2472-1727
• DOI: 10.1002/bdr2.2235

BackgroundBartter syndrome (BS) is a rare congenital salt‐losing renal tubular transport disorder, characterized by salt wasting, polyuria, biochemical abnormalities, and acid–base homeostasis imbalance. The syndrome has five different genetic forms, and novel mutations of CLCNKB gene lead to type 3 BS also known as classic BS. In this case, we report clinical and molecular findings from a newborn baby with BS.CaseA 10‐day‐old male infant born at 37 weeks of gestation by cesarean section following a pregnancy complicated with polyhydramnios, and fetal distress to a 30‐year‐old gravida 3, para 3 mother, with a 2500 g birth weight was brought to the pediatric emergency department due to weight loss and jaundice. The neonate was referred to the neonatal intensive care unit (NICU) with a preliminary diagnosis of hyponatremic dehydration (Na: 122 mmol/L, 10% dehydration) and hypokalemic hypochloremic metabolic alkalosis (K: 2.13 mmol/L, Cl: 63 mmol/L, pH: 7.62, pCO2: 39 mmHg, HCO3: 40.8 mmol/L, BE: 16.9 mmol/L), and hypocalcemia (ionized Ca: 0.72 mmol/L). On arrival to the NICU, symptomatic focal seizures, and polyuria complicated his course. Spot urine biochemistry revealed a renal salt wasting and hypercalciuria: Creatine 11.4 mg/dL Na: 51 mmol/L (54–150), K: 26 mmol/L (20–80), Cl: 164 mmol/L, fractional excretion of sodium (FENa): 3% (0.9–1.6), fractional excretion of chloride (FECl): 17% (