ESPN 54th Annual Meeting

ESPN 2022


 
Autosomal dominant hypocalcemia. When Bartter syndrome "pushes boundaries"
MARTA JIMéNEZ MORENO 1 PEDRO ARANGO SANCHO 1 ANA CRISTINA AGUILAR RODRíGUEZ 1 RAQUEL JIMéNEZ GARCíA 1 ELENA CODINA SAMPERA 1 YOLANDA CALZADA BAñOS 1 ÁLVARO MADRID ARIS 1

1- HOSPITAL SANT JOAN DE DéU
 
Introduction:

Bartter syndrome (BS) is a heterogeneous disorder related to multiple genetic mutations in transporters located in the thick loop of Henle.In 2002 it was described that autosomal dominant hypocalcemia (ADH) can be associated with BS.The calcium-sensitive receptor (CaSR) is a G protein-coupled receptor that is responsible for regulating calcium hemostasis,controlling the secretion of parathormone (PTH) and renal calcium excretion.Activating mutations of CaSR lead to inhibition of the ROMK channel and inhibit PTH production because of hypocalcemia.The clinical presentations and time of onset of the Bartter phenotype differ according to the type of mutation

Material and methods:

A 6-year-old patient who consulted for colic abdominal pain and 24-hour paresthesia in hands and feet.Born at term, blood tests with ions and normal PTH at birth.Under follow-up for non-compaction cardiomyopathy.Asymptomatic to date.Mother,aunt (twins) and maternal cousin in follow-up with endocrinology and cardiology with current diagnoses of pseudohypoparathyroidism and non-compaction cardiomyopathy

Results:

The initial study revealed hypokalemic metabolic alkalosis (potassium 2.5 mmol/l),hypomagnesemia and hypocalcemia,abnormally normal PTH for serum calcium.In the urine,hypercalciuria (calcium/creatinine ratio 1.02 mg/mg) is noted,with elevated fractional excretions of sodium,chloride,potassium and transtubular potassium gradient (TTKG).Renal ultrasound showing severe bilateral nephrocalcinosis.Given the suspicion of Bartter syndrome associated with an alteration in phosphocalcic metabolism, a genetic study was carried out detecting an activating mutation of the CaSR both in the patient and her relatives,being diagnosed with autosomal dominant hypocalcemia associated with Bartter syndrome

Conclusions:

When faced with patients with characteristics of renal salt-wasting syndrome together with alterations in phosphocalcic metabolism (hypocalcaemia and hypomagnesaemia),we must consider the differential diagnosis with this rare entity.At the present time,genetic results are pending for the patients heart disease,since no relationship between the two pathologies has been described to date.The genetic study avoids erroneous diagnoses allowing an adequate optimization of the treatment from the early stages of the disease,as well as the planning of a genetic advice before possible future pregnancies