Simultaneous Homozygous Mutations in SLC12A3 and CLCNKB in an Inbred Chinese Pedigree.

Gitelman syndrome (GS) and Bartter syndrome (BS) type III are both rare, recessively inherited salt-losing tubulopathies caused by SLC12A3 and CLCNKB mutations, respectively. We described a 48-year-old male patient with fatigue, carpopedal spasm, arthralgia, hypokalemic alkalosis, mild renal dysfunction, hypomagnesemia, hypocalciuria, hyperuricemia, normotension, hyperreninemia and chondrocalcinosis in knees and Achilles tendons. His parents are first cousin. Genetic analysis revealed simultaneous homozygous mutations in SLC12A3 gene with c.248G>A, p.Arg83Gln and CLCNKB gene with c.1171T>C, p.Trp391Arg. The second younger brother of the proband harbored the same simultaneous mutations in SLC12A3 and CLCNKB and exhibited similar clinical features except normomagnesemia and bilateral kidney stones. The first younger brother of the proband harbored the same homozygous mutations in CLCNKB and exhibited clinical features of hypokalemia, normomagnesemia, hypercalciuria and hyperuricemia. Potassium chloride, spironolactone and potassium magnesium aspartate were prescribed to the proband to correct electrolytic disturbances. Benzbromarone and febuxostat were prescribed to correct hyperuricemia. The dose of potassium magnesium aspartate was subsequently increased to alleviate arthralgia resulting from calcium pyrophosphate deposition disease (CPPD). To the best of our knowledge, we are the first to report an exceptionally rare case in an inbred Chinese pedigree with simultaneous homozygous mutations in SLC12A3 and CLCNKB. GS and BS type III have significant intrafamilial phenotype heterogeneity. When arthralgia is developed in patients with GS and BS, gout and CPPD should both be considered.

High angiotensin II state without cardiac remodeling (Bartter's and Gitelman's syndromes): are angiotensin II type 2 receptors involved?

BACKGROUND/AIMS: While Angiotensin II (Ang II) is a major factor in the development of cardiomyocyte hypertrophy and a pivotal role for Ang II signals via ERK1/2 has been identified, mechanism(s) responsible are still unclear. As Bartter's and Gitelman's syndrome patients (BS/GS) have increased Ang II, and yet normo/hypotension, hyporesponsiveness to pressors and blunted Ang II signaling via type 1 receptors (AT1R), this study assesses BS/GS's left ventricular (LV) mass and structure as well as Ang II induced ERK1/2 phosphorylation compared with essential hypertensive patients (EH) and normotensive healthy subjects (C) to gain insight into Ang II mediated processes. METHODS: Indices of cardiac hypertrophy were determined by M-mode, two-dimensional echo Doppler and ERK phosphorylation by Western blot. RESULTS: None of BS/GS exhibited LV remodelling; LV mass, LV end-diastolic volume and mass/volume ratio were unchanged vs C (60+/-14 g/m2 vs 64+/-12, 64+/-12 ml/m2 vs 60+/-8 and 0.95+/-0.2 vs 1.0+/-0.2, respectively) and reduced vs EH (119+/-15, p<0.001, 78+/-9, p<0.05 and 1.52+/-0.15, p<0.01). Despite BS/GS's higher plasma renin activity and aldosterone and unchanged level of AT1R, Ang II induced ERK1/2 phosphorylation was reduced vs both C and EH: 0.64 d.u.+/-0.08 vs 0.90+/-0.06 in C, p<0.006, and vs 1.45+/-0.07 in EH, p<0.001. CONCLUSION: The data point to a direct cardioremodeling role for Ang II and support a role of Ang II type 2 receptor (AT2R) signaling as involved in the lack of cardiovascular remodeling in BS/GS. However, further studies using more direct approaches to demonstrate the effects of AT2R signaling must be pursued.

[Polyhydramnios, prematurity, dystrophy, polyuria, constipation, nephrocalcinosis and renal tumor: presentation of a classic tubulopathy]. / Polyhydramnion, Frühgeburtlichkeit, Dystrophie, Polyurie, Obstipation, Nephrokalzinose und renale Raumforderung: Präsentation einer klassischen Tubulopathie.

BACKGROUND: A diagnostic workup of a renal mass will rarely lead to the diagnosis of a tubulopathy. We would like to stress the importance of taking a detailed history and of evaluating these findings in the context of the clinical symptoms. CASE REPORT: A 3 year old boy with a renal mass, diagnosed due to urinary tract infection, was referred to exclude renal malignancy. Detailed history revealed polyuria and polydipsia in a child with preterm delivery due to polyhydramnios. These symptoms, together with poor thriving are highly suggestive of a neonatal form of Bartter syndrome. This diagnosis was substantiated by ultrasound findings of nephrocalcinosis and urolithiasis due to hypercalciuria and a renal abscess. Detection of mutations in the KCNJ1-gene confirmed the diagnosis. After unilateral nephrectomy for acute destructive nephritis and under medication with indomethacin and potassium citrate the patient is now thriving well. CONCLUSION: Renal masses suspicious of malignancy may distract from a hereditary tubulopathy. Typical clinical history and presentation with prematurity, polyhydramnios, polyuria, poor thriving and urolithiasis requires diagnostic evaluation of tubular function since routine laboratory tests and urinary dip stick may be normal. Unrecognized, neonatal Bartter syndrome may lead to severe complications including loss of kidney function.

Abnormal captopril scintigraphy in Bartter syndrome.

A 37-year-old patient with severe hypokalemia (approximately 1.7 mEq/L) and muscular weakness had a very high serum renin level. No renin-producing tumor was found and she was diagnosed with Bartter Syndrome The parathyroid hormone level was high due to concomitant renal calcium loss. Tc-99m-DTPA captopril scintigraphy was performed to confirm the diagnosis.

Bartter's syndrome and captopril scintigraphy: a case report.

We report a case of a woman who came to our attention because of hypokalemia, hyperreninemia and hyperaldosteronemia but with normal blood pressure. Under suspicion of a normotensive renal artery stenosis captopril and baseline scintigraphies were performed. Captopril scintigraphy demonstrated a bilateral progressive retention of radiopharmaceutical without significant excretion. The baseline study revealed a complete normalization of the scintigraphyc picture. A Magnetic Resonance Angiography (Angio-MRI) performed to evaluate renal arteries gave completely normal results. On the basis of the clinical picture and imaging findings a diagnosis of Bartter's syndrome was formulated. Renal function in Bartter's syndrome patients is maintained by hyperactivation of the renin angiotensin system. Acute administration of captopril in these patients induces an increase of renal plasma flow whereas it has no effects on glomerular filtration rate thus inducing a decrease of the filtration fraction: post captopril renal scintigraphy of our patient depicted exactly this feature. Although the diagnosis of Bartter's syndrome is based on the clinical picture and biochemical abnormalities, scintigraphic tests could be useful in differentiating Bartter's syndrome from other causes of hypokalemia.

Bartter syndrome in a neonate: early treatment with indomethacin.

The neonatal form of Bartter syndrome is characterized by intrauterine onset of polyuria leading to severe polyhydramnios. We report a patient with the early onset of the syndrome and a similar history in a previous sibling who died in early neonatal life. The patient is a female product of 33 weeks of gestation complicated by severe polyhydramnios. Her birth weight was 2,100 g. Polyuria led to severe dehydration on the 3rd day of life. Laboratory studies showed hypokalemia, hyponatremia, and elevated plasma levels of renin and aldosterone. Hypercalciuria was associated with echographic evidence of nephrocalcinosis. Indomethacin therapy resulted in a significant reduction in urine volume and correction of biochemical abnormalities. Growth and development are satisfactory after 4 years of indomethacin therapy, but nephrocalcinosis remains unchanged.

Prenatal and postnatal management of hyperprostaglandin E syndrome after genetic diagnosis from amniocytes.

OBJECTIVE: To describe prenatal genetic diagnosis in hyperprostaglandin E syndrome (HPS) and the effect of indomethacin therapy on the course of the disease before birth and in the neonatal period. METHODS: Mutational analysis of the ROMK channel gene (KCNJ1) from amniocytes by single-strand conformational analysis and direct sequencing. Review of the clinical and laboratory findings during pregnancy and the neonatal period in two siblings affected with HPS. RESULTS: Compound heterozygosity of the fetus in KCNJ1 (D74Y/P110L) confirmed the clinical diagnosis of HPS at 26 weeks of gestation. Indomethacin therapy from 26 to 31 weeks prevented further progression of polyhydramnios without major side effects. In contrast to the elder brother, who had been diagnosed at the age of 2 months, the neonatal course was uncomplicated. Hypovolemic renal failure after excessive renal loss of salt and water could be prevented and severe nephrocalcinosis did not occur. CONCLUSIONS: Genetic diagnosis of HPS and subsequent prenatal indomethacin therapy seems to have a beneficial effect on the natural course of HPS, especially progression of polyhydramnios; therefore, extreme prematurity could be prevented. Also, postnatally the early diagnosis allows the effective water and electrolyte substitution before severe volume depletion.

Renal sonographic patterns in Bartter's syndrome.

The renal sonographic findings in ten cases of Bartter s syndrome investigated at the King Khalid University Hospital, Riyadh, Saudi Arabia are described. There were various sonographic abnormalities other than those of hyperechoic pyramids as previously described. These were diffuse increased renal echogenicity and hyperechoic echogenicity in the kidneys with the exception of the pyramids. This condition can be suspected early if nephrocalcinosis is present in a child with a history of polyhydramnios and premature delivery.

Evidence for cardiovascular remodeling in a patient with Bartter's syndrome.

In a 56-year-old normotensive white male subject with a 12-year history of hypokalemic alkalosis, hyperreninemia, and aldosteronism, the diagnosis of Bartter's syndrome was established on the basis of an impaired maximal renal diluting capacity and decreased distal fractional chloride absorption [CH2O/(CH2O+CCl)]. Negative urine analysis for diuretics suggested that this renal tubular defect was not secondary to diuretic (ab)use. In this normotensive patient with hyperreninemia and secondary aldosteronism, significant cardiovascular remodeling could be observed. Thus, in spite of normal arterial blood pressure and normal left ventricular systolic function (ejection fraction > 70%), impaired left ventricular diastolic function was observed using pulsed-wave Doppler echocardiography. Moreover, duplex analysis of the common carotid artery revealed significant intima-media hypertrophy with an average intima-media diameter of 0.9 mm (normal < or = 0.6 mm). Also, forearm venous occlusion plethysmography revealed an abnormally high minimal forearm vascular resistance following a 10-min period of forearm ischemia handgrip exercise suggesting remodeling within the peripheral arterioles. Thus, in a patient with Bartter's syndrome and activated neurohormonal systems such as the renin-angiotensin system, cardiac and vascular remodeling can be observed in the absence of hypertension. In analogy to the results of experimental studies showing that angiotensin II and noradrenaline act as growth factors on cardiac and vascular cells, cardiovascular remodeling present in our patient with Bartter's syndrome may be explained by increased activity of angiotensin II and/or noradrenaline.

Familial hypokalemia/hypomagnesemia and chondrocalcinosis.

OBJECTIVE: Familial occurrence of Bartter's syndrome is well known, but the simultaneous occurrence of hypokalemia/hypomagnesemia and chondrocalcinosis in one family has not been described. We present the clinical, laboratory and radiological findings of a family, in which 7 members were affected by disease. METHODS: A total of 43 members of the family could be interviewed concerning their general health, past diseases and joint complaints. Serum potassium and magnesium were determined in all and radiographic studies were performed in those who had hypokalemia and hypomagnesemia or those with merely articular complaints. Urinary excretion of potassium, magnesium and calcium were determined in the affected persons. RESULTS: Seven patients were found with hypokalemia and hypomagnesemia. Urinary potassium and magnesium excretion was inappropriately high when compared to the serum levels of these electrolytes. All patients had hypocalciuria and extensive chondrocalcinosis, mainly in the knees, elbows and shoulders. In one patient, most probably as a result of magnesium supplementation, a striking reduction of chondrocalcinosis was observed during a followup of 10 years. CONCLUSION: A family with familial hypokalemia/hypomagnesemia and chondrocalcinosis is described. The reduction of chondrocalcinosis, after years of magnesium supplementation in one patient, suggests that hypomagnesemia is an important factor in the pathogenesis of chondrocalcinosis in these patients.

Hyperechoic renal medullary pyramids in infants and children.

Fifty-five children (34 boys, 21 girls; age range, 1 day to 18 years) with increased echogenicity of the renal medullary pyramids at ultrasound evaluation were identified. The clinical diagnoses associated with hyperechoic medullary pyramids could be separated based on the presence or absence of hypercalciuria. Patients with drug-induced hypercalciuria included 10 infants treated with furosemide, two treated with long-term steroid therapy, and one treated with excessive amounts of vitamin D. Other clinical conditions associated with hypercalciuria included renal tubular acidosis (n = 10), Bartter syndrome (n = 5), hyperparathyroidism (n = 3), Williams syndrome (n = 2) and medullary sponge kidney (n = 2). Ten children with transient renal insufficiency and three with sickle cell disease had normal urine calcium concentration. Isolated disease entities accounted for the remainder of cases. A specific diagnosis can usually be made in a patient with hyperechoic renal medullary pyramids by using a systematic clinical approach that includes evaluation of patient age, serum and urine calcium concentration, and renal function.

[Maternal Bartter syndrome and pregnancy]. / Anyai Bartter-szindróma és terhesség.

The course of pregnancy, the parturition and postpartal period of a 19-year-old caucasian woman with Bartter syndrome was described. The pathogenesis, diagnosis, complications and the prenatal course of the autosomal recessive condition was also described by reviewing literary and own data. Analysis of amniotic fluid and ultrasound measurements showed unaffected fetus. The purpose of the paper was to summarize the suggested and recently applied prenatal care, maternal and fetal diagnostic and therapeutic measures in case of Bartter syndrome. Special emphasis was made on the prevention of fetal intrauterin growth retardation which frequently occurs in this condition.

Nephrocalcinosis in Bartter's syndrome.

Nephrocalcinosis was demonstrated by computerized tomography (CT) in all five children with Bartter's syndrome followed at our institution. In three of these five patients, nephrocalcinosis was also noted on ultrasound examination. Hypercalciuria was present in only one case. The mechanism leading to renal calcification remains unclear in this disease. It is noteworthy, however, that Bartter's syndrome is associated with such a high incidence of nephrocalcinosis.

Unusual radiological changes associated with probable Bartter's syndrome.

We report 2 cases that fulfill some of the criteria for the diagnosis of Bartter's syndrome and were associated with marked radiological changes. Both patients demonstrated distortion of the caliceal pattern with medullary cavities and loss of cortical substance in the absence of vesicoureteral reflux. However, the glomerular filtration rate was well preserved. It seems unlikely that known organic renal disease was responsible for these changes and the potassium-losing state. These radiological findings also do not appear to be a consequence of hypokalemia and their pathogenesis remains uncertain.

Clinical experience with 75Se selenomethylcholesterol adrenal imaging.

The results of quantitative adrenal imaging using 75Se selenomethylcholesterol in sixty-two subjects are analysed. The adrenal area was localized by a renal scan, lateral views of which enabled adrenal depth to be estimated. The first nineteen cases were scanned with a rectilinear scanner and the remaining forty-three cases imaged with a gamma camera. Quantitation of adrenal uptake was performed on computer-stored static images obtained 7 and 14 days post-injection of 75Se selenomethylcholesterol (3 and 6 days in the first ten cases studied). Normal uptake was found to be 0.07-0.30% of the administered dose. Overall predictive accuracy of the type of adrenal disorder of thirty-two patients with Cushing's syndrome ws 90.6%, this included twelve cases of Cushing's disease (mean uptake 0.58%), seven ectopic ACTH syndromes (mean uptake 0.69%), five unilateral adenomata (mean uptake 0.93%), three post adrenalectomy regrowths (mean uptake 1.37%), three adrenal carcinomas (mean uptake 0.01%), one congenital hyperplasia (mean uptake 3.4%) and one unilateral nodular hyperplasia. Overall predictive accuracy of the cause of Conn's syndrome in twenty-two cases was 86.4%; this included thirteen cases of bilateral hyperplasia (mean uptake 0.34%), eight unilateral adenomata (mean uptake 0.47%) and one patient with mineralocorticoid excess in whom the cause has not been confirmed. The mean uptake in the normal adrenal in cases of unilateral adenoma was 0.19% (range 0.07-0.30%). Causes of unsatisfactory adrenal imaging are examined. The procedure is recommended as the localizing and lateralizing technique of choice in Cushing's syndrome except where due to adrenal carcinoma, and as an important non-invasive technique in Conn's syndrome for the lateralization of adenoma.