Esotropia, nystagmus and optic disk staphyloma in Donnai-Barrow syndrome / Esotropia, nistagmo e estafiloma de disco óptico na síndrome de Donnai-Barrow

ABSTRACT A 12-year-old boy with Donnai-Barrow syndrome diagnosed intra-uterus presented esotropia, high myopia, nystagmus, and optic disk staphyloma in an ophthalmologic examination. The patient had associated Fanconi syndrome and sensorineural hearing loss as well as facial manifestations as hypertelorism, downward slanting of palpebral fissures and low ear implantation. Magnetic resonance imaging revealed agenesis of the corpus callosum. To our knowledge, this is the first reported case associated with esotropia, nystagmus, and optic disk staphyloma.

RESUMO Paciente do sexo masculino, 12 anos, com diagnóstico intrauterino de síndrome de Donnai-Barrow, apresentava ao exame oftalmológico esotropia, alta miopia, nistagmo e estafiloma de disco óptico. Associado ao quadro, apresentava síndrome de Falconi e perda auditiva neurossensorial, além de alterações faciais, como hipertelorismo, inclinação inferior das fissuras palpebrais e implantação baixa das orelhas. Ressonância magnética revelou agenesia de corpo caloso. Ao nosso conhecimento, este é o primeiro caso relatado associando esotropia, nistagmo e estafiloma de disco óptico.

Hypomagnesemia with Hypercalciuria Leading to Nephrocalcinosis, Amelogenesis Imperfecta, and Short Stature in a Child Carrying a Homozygous Deletion in the CLDN16 Gene.

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive disease caused by mutations in the CLDN16 or CLDN19 gene; however, few cases develop classical amelogenesis imperfecta. Herein, we report the case of a boy with early clinical renal manifestations that started at 1 year of age and presenting with dental hypoplasia and growth delay. The patient presented with vomiting, polyuria, and polydipsia. Apart from recurrent sterile leukocyturia, erroneously treated as infectious, he was normal, except for short stature and amelogenesis imperfecta with gradually discolored teeth. Laboratory tests revealed hyperparathyroidism, hypomagnesemia, severe hypercalciuria, and hypermagnesuria on 24-h urine testing. Helical computed tomography confirmed nephrocalcinosis. We performed whole-exome sequencing (WES) to test the hypothesis of FHHNC and oligogenic inheritance of amelogenesis. Analysis of the WES binary sequence alignment/map file revealed the presence of exon 1 of the CLDN16 and absence of the other exons [c.325_c918*? (E2_E5del)]. We confirmed a CLDN16 E2_E5 homozygous deletion by multiplex ligation-dependent probe amplification and polymerase chain reaction assays. Although most mutations causing FHHNC are missense and nonsense mutations in the CLDN16 or CLDN19 gene, large deletions occur and may be misled by WES, which is generally used for genetic screening of oligogenic disorders. The patient received cholecalciferol, magnesium oxide and potassium citrate. Later, the combination with hydrochlorothiazide plus amiloride was prescribed, with a good response during follow-up. Our report broadens the phenotype of FHHNC, including severe early-onset amelogenesis and short stature, and reinforces the phenotype-genotype correlation of the large deletion found in CLDN16.

Hypouricemia: what the practicing rheumatologist should know about this condition.

We presented an update in the field of hypouricemia, which is defined as a serum urate concentration of < 2 mg/dL (119 µmol/L), for the practicing rheumatologist, who usually is the consulting physician in cases of disorders of urate metabolism. We performed a narrative review through a literature search for original and review articles in the field of human hypouricemia published between January 1950 and July 2018. We divided the etiology of hypouricemia into two main categories: those associated with a decrease in urate production and those promoting the elimination of urate via the kidneys. The most common conditions associated with these categories are discussed. Furthermore, the etiology of hypouricemia may be associated with certain medications prescribed by the practicing rheumatologists, such as the following: urate-lowering drugs (allopurinol and febuxostat); recombinant uricase (pegloticase); uricosuric agents (probenecid, benzbromarone); urate transporter URAT1 inhibitor (lesinurad); angiotensin II receptor blocker (losartan); fenofibrate; high-dose trimethoprim-sulfamethoxazole; some NSAID; and high-dose salicylate therapy. The rheumatologist is considered an expert in the metabolism of urate and its associated pathological conditions. Therefore, specialists must recognize hypouricemia as a biomarker of various pathological and potentially harmful conditions, highlighting the importance of conducting a deeper clinical investigation to reach a more accurate diagnosis and treatment.

Mineral Disorders in Adult Inpatients Receiving Parenteral Nutrition. Is Older Age a Contributory Factor?

BACKGROUND: Parenteral nutrition (PN)-dependent adults and elderly individuals who are admitted to hospital treatment are potentially susceptible to mineral disorder complications due to depleted physiological reserves, loss of lean body mass, and increased fat mass, thus worsening inflammation. AIM: The purpose of this study is to evaluate the prevalence of hypophosphatemia, hypokalemia, and hypomagnesaemia prior and within the first 7 days of PN infusion. Furthermore, whether malnutrition and old age are associated with these disorders was also investigated. METHODS: This study included a historical cohort of adult patients, and 1,040 patients whose information was prospectively entered in the database were evaluated. RESULTS: Of the 781 patients, 27.3% were ≥65 years, 80.9% had undergone surgical treatment, 74.3% were in the intensive care unit, and 17.9% died during the hospitalization period. About 17.1% patients were malnourished. Protein energy malnutrition (PEM) was observed in 31.9% of the elderly patients and 27.1% of adults in general. Hypophosphatemia, hypokalemia, and hypomagnesemia were more prevalent before the start of PN infusion (D0: 214 [18.4%]), and new events were more common during the first 2 days of PN infusion (D1: 283 [23.1%]; D2: 243 [20.1%]. Elderly patients were more susceptible to developing hypophosphatemia (odds ratio [OR]: 1.69; 95% confidence interval [CI]: 1.29-2.19; p<0.001). Patients with PEM were also more susceptible to hypophosphatemia (OR: 3.75; 95% CI: 1.13-12.47; p=0.036). CONCLUSION: Hypophosphatemia, hypokalemia, and hypomagnesemia were frequently observed in hospitalized adults and elderly patients before and particularly during the first 2 days of PN infusion. Elderly patients and patients with PEM are more susceptible to developing hypophosphatemia.

Effect of magnesium supplementation on insulin resistance in humans: A systematic review.

OBJECTIVES: Recent studies have demonstrated that minerals play a role in glucose metabolism disorders in humans. Magnesium, in particular, is an extensively studied mineral that has been shown to function in the management of hyperglycemia, hyperinsulinemia, and insulin resistance (IR) action. The aim of this study was to investigate the effect of magnesium supplementation on IR in humans via systematic review of the available clinical trials. METHODS: This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. A survey was conducted to select clinical trials related to the effects of this mineral in insulin sensitivity using the following databases: PubMed, SciVerse Scopus, ScienceDirect, and SciVerse Cochrane. RESULTS: After the selection process, 12 articles were identified as eligible, representing different clinical conditions and being free of restriction with regard to sex, age, ethnicity, and differential dosing/shape of magnesium. The results of eight clinical trials showed that supplementation with magnesium influences serum fasting glucose concentrations, and five trials determined an effect on fasting insulin levels. The results of seven studies demonstrated that mineral supplementation reduced homeostasis model assessment for IR values. CONCLUSIONS: The data of this systematic review provide evidence as to the benefits of magnesium supplementation in reducing IR in patients with hypomagnesemia presenting IR. However, new intervention studies are needed to elucidate the role of the nutrient in protection against this metabolic disorder, as well as the standardization of the type, dose, and time of magnesium supplementation.

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis: variable phenotypic expression in three affected sisters from Mexican ancestry.

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare autosomal recessive renal disease caused by mutations in genes for the tight junction transmembrane proteins Claudin-16 (CLDN16) and Claudin-19 (CLDN19). We present the first case report of a Mexican family with three affected sisters carrying a p.Gly20Asp mutation in CLDN19 whose heterozygous mother showed evident hypercalciuria and normal low magnesemia without any other clinical, laboratory, and radiological symptoms of renal disease making of her an unsuitable donor. The affected sisters showed variable phenotypic expression including age of first symptoms, renal urinary tract infections, nephrolithiasis, nephrocalcinosis, and eye symptoms consisting in retinochoroiditis, strabismus, macular scars, bilateral anisocoria, and severe myopia and astigmatism. End stage renal disease due to renal failure needed kidney transplantation in the three of them. Interesting findings were a heterozygous mother with asymptomatic hypercalciuria warning on the need of carefully explore clinical, laboratory, kidney ultrasonograpy, and mutation status in first degree asymptomatic relatives to avoid inappropriate kidney donors; an evident variable phenotypic expression among patients; the identification of a mutation almost confined to Spanish cases and a 3.5 Mb block of genomic homozygosis strongly suggesting a common remote parental ancestor for the gene mutation reported.

Five years results after intrafamilial kidney post-transplant in a case of familial hypomagnesemia due to a claudin-19 mutation.

INTRODUCTION: Familial Hypomagnesaemia with hypercalciuria and nephrocalcinosis, with severe ocular impairment secondary to claudin-19 mutation, is a rare recessive autossomic disorder. Its spectrum includes renal Mg2+ wasting, medullary nephrocalcinosis and progressive chronic renal failure in young people. OBJECTIVE: To report a case of kidney transplantation father to daughter in a familial occurrence of severe bilateral nephrocalcinosis associated with ocular impairment in a non-consanguineous Brazilian family, in which two daughters had nephrocalcinosis and severe retinopathy. METHODS: The index case, a 19 years-old female, had long-lasting past medical history of recurrent urinary tract infections, and the abdominal X-ray revealed bilateral multiple renal calcifications as well as ureteral lithiasis, and she was under haemodialysis. She had the diagnosis of retinitis pigmentosa in the early neonatal period. The other daughter (13 years-old) had also nephrocalcinosis with preserved kidney function, retinopathy with severe visual impairment, and in addition, she exhibited hypomagnesaemia = 0.5 mg/dL and hypercalciuria. The other family members (mother, father and son) had no clinical disease manifestation. Mutation analysis at claudin-19 revealed two heterozygous missense mutations (P28L and G20D) in both affected daughters. The other family members exhibited mutant monoallelic status. In despite of that, the index case underwent intrafamilial living donor kidney transplantation (father). CONCLUSION: In conclusion, the disease was characterized by an autosomal recessive compound heterozygous status and, after five years of donation the renal graft function remained stable without recurrence of metabolic disturbances or nephrocalcinosis. Besides, donor single kidney Mg2+ and Ca2+ homeostasis associated to monoallelic status did not affect the safety and the usual living donor post-transplant clinical course.

Five years results after intrafamilial kidney post-transplant in a case of familial hypomagnesemia due to a claudin-19 mutation / Resultado cinco anos pós-transplante renal intrafamiliar em um caso de hipomagnesemia familiar devido a mutação da claudina-19

Introduction: Familial Hypomagnesaemia with hypercalciuria and nephrocalcinosis, with severe ocular impairment secondary to claudin-19 mutation, is a rare recessive autossomic disorder. Its spectrum includes renal Mg2+ wasting, medullary nephrocalcinosis and progressive chronic renal failure in young people. Objective: To report a case of kidney transplantation father to daughter in a familial occurrence of severe bilateral nephrocalcinosis associated with ocular impairment in a non-consanguineous Brazilian family, in which two daughters had nephrocalcinosis and severe retinopathy. Methods: The index case, a 19 years-old female, had long-lasting past medical history of recurrent urinary tract infections, and the abdominal X-ray revealed bilateral multiple renal calcifications as well as ureteral lithiasis, and she was under haemodialysis. She had the diagnosis of retinitis pigmentosa in the early neonatal period. The other daughter (13 years-old) had also nephrocalcinosis with preserved kidney function, retinopathy with severe visual impairment, and in addition, she exhibited hypomagnesaemia = 0.5 mg/dL and hypercalciuria. The other family members (mother, father and son) had no clinical disease manifestation. Mutation analysis at claudin-19 revealed two heterozygous missense mutations (P28L and G20D) in both affected daughters. The other family members exhibited mutant monoallelic status. In despite of that, the index case underwent intrafamilial living donor kidney transplantation (father). Conclusion: In conclusion, the disease was characterized by an autosomal recessive compound heterozygous status and, after five years of donation the renal graft function remained stable without recurrence of metabolic disturbances or nephrocalcinosis. Besides, donor single kidney Mg2+ and Ca2+ homeostasis associated to monoallelic status did not affect the safety and the usual living donor post-transplant clinical course. .

Introdução: Hipomagnesemia familiar com hipercalciúria e nefrocalcinose, com grave envolvimento ocular, por mutação no gene da claudina-19, é uma doença rara autossômica recessiva. Seu espectro inclui perda renal de magnésio, nefrocalcinose medular e doença renal progressiva em crianças e adolescentes. Objetivo: Relatar um caso de transplante renal pai para filha em uma ocorrência familiar de nefrocalcinose bilateral grave associada com comprometimento ocular em uma família brasileira não consangüínea, na qual duas filhas apresentavam nefrocalcinose e retinopatia severa. Métodos: O caso índice, uma mulher de 19 anos de idade, tinha longa história pregressa de infecção urinária de repetição, o raio-X abdominal revelava calcificações renais múltiplas bilaterais, bem como litíase ureteral, e estava sob hemodiálise. Havia um diagnóstico prévio de retinite pigmentosa no período neonatal precoce. A outra filha (13 anos de idade) também apresentava nefrocalcinose com função renal preservada, retinopatia com grave deficiência visual, e além disso, ela exibia hipomagnesemia = 0,5 mg/dL e hipercalciúria. Os outros membros da família (mãe, pai e filho) não tinham nenhuma manifestação clínica da doença. A análise mutacional no gene da claudin-19 revelou duas mutações heterozigotas (P28L e G20D) em ambas as filhas afetadas. Os outros membros da família apresentavam estado mutante monoalélico. Apesar disso, o caso índice foi submetido a transplante de rim com doador vivo intrafamiliar (pai). Conclusão: Em conclusão, a doença foi caracterizada por um estado heterozigoto recessivo composto autossômico e após cinco anos de doação a função do enxerto ...

Oral magnesium supplementation decreases C-reactive protein levels in subjects with prediabetes and hypomagnesemia: a clinical randomized double-blind placebo-controlled trial.

BACKGROUND AND AIMS: It has been suggested that magnesium deficiency is associated with the triggering of acute phase response, which may contribute to type 2 diabetes and cardiovascular disease risk. We undertook this study to determine whether oral magnesium supplementation modifies serum levels of high-sensitivity C-reactive protein (hsCRP) in apparently healthy subjects with prediabetes and hypomagnesemia. METHODS: A total of 62 men and non-pregnant women aged 18-65 year, with new diagnosis of prediabetes (glucose 5.6 <7.0 mmol/L and/or post-load glucose ≥7.7 <11.1 mmol/L) and hypomagnesemia (serum magnesium levels <0.74 mmol/L) were enrolled in a clinical double-blind placebo-controlled trial and randomly allocated to receive either magnesium chloride (30 mL of MgCl2 5% solution) or NaHCO3 0.1% solution, once daily for 3 months. RESULTS: At basal conditions, anthropometric and biochemical variables were similarly distributed in both groups. At the end of follow-up, participants who received magnesium chloride showed higher serum magnesium levels (0.86 ± 0.08 vs. 0.69 ± 0.16 mmol/L, p = 0.002) and lower hsCRP levels (4.8 ± 15.2 vs. 17.1 ± 21.0 nmol/L, p = 0.01) compared with participants in the control group. CONCLUSIONS: Oral magnesium supplementation decreases hsCRP levels in apparently healthy subjects with prediabetes and hypomagnesemia.

"Ghosts in my body": Seizure-like presentation of hypocalcemic tetany secondary to hypomagnesemia in a patient receiving cetuximab therapy for metastatic medulloblastoma.

Cetuximab, a monoclonal antibody specific for epidermal growth factor receptor, is increasingly used off-label and in early-phase trials for pediatric malignancies. Here, we report a patient with metastatic medulloblastoma receiving therapy with cyclophosphamide, vinblastine, and cetuximab. During evaluation for possible seizures, he was noted to be severely hypocalcemic, hypokalemic, and hypomagnesemic, a consequence of the blockade of renal epidermal growth factor receptor expression. His symptoms rapidly abated with intravenous electrolyte repletion. This case highlights the clinical heterogeneity of tetany and the importance of careful laboratory screening for known adverse effects of chemotherapy, particularly when newer biological agents are used off-study in combination chemotherapeutic regimens.

No positive effect of oral magnesium supplementation in the decreases of inflammation in subjects with prediabetes: a pilot study.

To determine whether oral magnesium supplementation modifies serum levels of high-sensitivity C-reactive protein (hsCRP), TNF-alpha, IL-6, and IL-10 in subjects with prediabetes, inflammation, and hypomagnesemia, a total of 26 subjects men and non-pregnant women were included and randomly allocated to receive 30 ml of MgCl(2) 5% solution (equivalent to 382 mg of magnesium) or placebo, daily during three months. At baseline conditions, there were not significant statistical differences between the groups. At end of the study, hsCRP levels were significantly lower in the intervention group (3.3 ± 2.5 vs 8.0 ± 5.9 mg/L, p = 0.03), as compared with the control group. However, the intra-group analysis of the individuals who received magnesium, did not shows significant statistical differences between baseline and final conditions (4.1 ± 3.0 and 3.3 ± 2.5, p = 0.45). In addition, TNF-alpha (1.2 ± 0.3 vs 1.1 ± 0.3 pg/mL, p = 0.69), IL-6 (0.3 ± 0.3 vs 5.0 ± 7.7 pg/mL, p = 0.08), and IL-10 (1.8 ± 0.4 vs 1.8 ± 0.5 pg/mL, p = 0.89) serum levels were not significantly different between the groups. Our results do not show a beneficial effect of oral magnesium supplementation on hsCRP, IL-6, TNF-alpha, and IL-10 levels in prediabetic subjects with hypomagnesemia and inflammation. Further studies with large sample sizes and longer time of follow-up are necessaries to verify the results of our pilot study.

High cholesterol feeding may induce tubular dysfunction resulting in hypomagnesemia.

BACKGROUND/AIMS: Hypomagnesemia may induce hypercholesterolemia, but the contrary has not been described yet. Thus, magnesium homeostasis was evaluated in rats fed a cholesterol-enriched diet for 8 days. This study has a relevant clinical application if hypomagnesemia, due to hypercholesterolemia, is confirmed in patients with long-term hypercholesterolemia. METHODS: Both hypercholesterolemic (HC) and normocholesterolemic rats (NC) were divided into sets of experiments to measure hemodynamic parameters, physiological data, maximum capacity to dilute urine (C(H)((2))(O)), variations (Δ) in [Ca(2+)](i) and the expression of transporter proteins. RESULTS: HC developed hypomagnesemia and showed high magnesuria in the absence of hemodynamic abnormalities. However, the urinary sodium excretion and C(H)((2))(O) in HC was similar to NC. On the other hand, the responses to angiotensin II by measuring Δ [Ca(2+)](i) were higher in the thick ascending limb of Henle's loop (TAL) of HC than NC. Moreover, high expression of the cotransporter NKCC2 was found in renal outer medulla fractions of HC. Taken together, the hypothesis of impairment in TAL was excluded. Actually, the expression of the epithelial Mg(2+) channel in renal cortical membrane fractions was reduced in HC. CONCLUSION: Impairment in distal convoluted tubule induced by hypercholesterolemia explains high magnesuria and hypomagnesemia observed in HC.

Presentación de un caso con múltiples malformaciones congénitas: asociación VACTERL / A case with multiple congenital malformations: VACTERL association

La asociación VACTERL es un conjunto de malformaciones congénitas que ocurre en varias combinaciones, entre las cuales encontramos: malformaciones Vertebrales, atresia Anal, anomalías Cardiovasculares, fistula Traqueo esofágica, atresia Esofágica, malformaciones Renales y displasia de las extremidades (Limb), fundamentalmente en el hueso radial. Para su diagnóstico se requiere la presencia de, al menos, tres de los siete criterios enumerados y se realiza por medio de ecografía a partir de la semana 18 de gestación. Aun no se ha reconocido etiología específica para esta patología; se cree que es producto de una influencia teratogénica entre la cuarta y octava semana de gestación. El pronóstico de estos pacientes es muy pobre, ya que fallece el 50-85% de los niños en el primer año de vida, sobreviviendo después del primer año de vida solo un 12-15%.

VACTERL association is a group of birth defects occurring in various combinations, among which are: vertebral anomalies, anal atresia, cardiac defects, tracheo-oesophageal fistula with esophageal atresia, renal defects and limb dysplasia, mainly in the radial bone. To diagnostic is necessary at least three of the seven criteria listed and is performed by ultrasound after 18 weeks of gestation. Although no specific etiology has been recognized for this condition, is believed to be the result of undefined teratogenic influence acting between the fourth and eighth weeks of gestation. Prognosis for these patients is very poor, and who died on 50-85% of children in the first year and surviving after the first year of life only 12-15%.

Behavioral and neurochemical effects of proline.

Proline is an amino acid with an essential role for primary metabolism and physiologic functions. Hyperprolinemia results from the deficiency of specific enzymes for proline catabolism, leading to tissue accumulation of this amino acid. Hyperprolinemic patients can present neurological symptoms and brain abnormalities, whose aetiopathogenesis is poorly understood. This review addresses some of the findings obtained, mainly from animal studies, indicating that high proline levels may be associated to neuropathophysiology of some disorders. In this context, it has been suggested that energy metabolism deficit, Na(+),K(+)-ATPase, kinase creatine, oxidative stress, excitotoxicity, lipid content, as well as purinergic and cholinergic systems are involved in the effect of proline on brain damage and spatial memory deficit. The discussion focuses on the relatively low antioxidant defenses of the brain and the vulnerability of neural tissue to reactive species. This offers new perspectives for potential therapeutic strategies for this condition, which may include the early use of appropriate antioxidants as a novel adjuvant therapy, besides the usual treatment based on special diets poor in proline.

[Familial hypomagnesemia, hypercalciuria with nephrocalcinosis syndrome: report of a case]. / Síndrome de hipomagnesemia familiar con hipercalciuria y nefrocalcinosis: presentación de un caso.

Familial hypomagnesemia and hypercalciuria with nephrocalcinosis is a rare autosomal recessive disease characterized by renal calcium and magnesium wasting, evolving in the progressive decrease of renal function, eventually requiring kidney transplant. Clinical findings include urinary infection, polyuria, polydipsia, cramps, tremors, convulsions, among others; these, associated to ocular and/or auditive abnormalities. We present a 4 year-old female with the syndrome, which was manifested by typical signs and symptoms in daily practice: fever, abdominal pain, polyuria and polydipsia. These symptoms may defer the diagnosis of the syndrome.

Dent-2 disease: a mild variant of Lowe syndrome.

OBJECTIVE: To compare the renal and extra-renal phenotypes of patients classified as having Dent disease, Dent-2 disease, or Lowe syndrome. STUDY DESIGN: Chart review of data from 93 patients with identified voltage-gated chloride channel and chloride/proton antiporter 5 gene and oculo-cerebro-renal syndrome of Lowe gene mutations observed by the authors, complemented with published data. RESULTS: There was a wide overlap of renal symptoms. Nephrocalcinosis was more prevalent in Dent-1 disease, and renal tubular acidosis, aminoaciduria, and renal failure was more prevalent in patients with Lowe syndrome. Patients with Lowe syndrome were shorter than patients with Dent-1 disease, and patients with Dent-2 disease showed an intermediate phenotype. Three patients with Dent-2 disease had mild peripheral cataract, and 9 patients were noted to have some degree of mental retardation. CONCLUSION: There is a phenotypic continuum within patients with Dent-2 disease and Lowe syndrome, suggesting that there are individual differences in the ability to compensate for loss of oculo-cerebro-renal syndrome of Lowe gene function.

Despistaje de acidosis tubular renal distal en preescolares del jardín de infancia Guiri Guire La Guardia, Estado Nueva Esparta: mayo 2005 / Search of acidosis renal distal in preeschool of the childhood garden Guiri Guire La Guardia, Nueva Esparta: may 2005

La acidosis tubular renal distal es un trastorno congénito o adquirido de la acidificación renal consecuencia de disfunción tubular, no presenta manifestaciones clínicas evidentes. Realizar despistaje en preescolares del Jardín de infancia Guiri Guire, La Guardia, Estado Nueva Esparta, en mayo 2005. Estudio Transversal mixto, muestra de 104 preescolares, se tallaron, pesaron, se llenó cuestionario respecto a hábitos alimentarios. Se realizó examen simple de primera orina en ayunas. Aquellos cuyo pH urinario resultó alcalino y/o presentaban cristales de oxalato de calcio pasaron a segunda etapa del estudio que consistió en recolectar muestra de 1ª y 2ª orina en ayunas, 2 muestras de sangre (en ayunas, post prandial) para determinar electrolitos séricos, urinarios, calcio, creatinina séricos, urinarios, y equilibrio ácido base. Los que presentaron acidosis metabólica hiperclorémica con hiato aniónico urinario positivo, se diagnósticaron como acidosis tubular renal distal. La incidencia es de 1,9 por ciento. Se evidenció alta prevalencia de cristales de oxalato de calcio en orina (26,92 por ciento). Del total se encontró un caso con acidosis metabólica hiperclorémica con hiato aniónico urinario negativo. La asociación entre talla baja y acidosis no fue estadísticamente significativa (p=0,906). La asociación entre déficit ponderal y acidosis no fue significativa (p=0,799). La prevalencia de esta patología (2/104) es significativamente mayor que la mundial (1/10000) (Probabilidad de Poisson = 0,00005352). Se recomienda realizar estudios con muestras de mayor tamaño para resultados más precisos del comportamiento de la enfermedad a nivel estatal.

A common NKCC2 mutation in Costa Rican Bartter's syndrome patients: evidence for a founder effect.

Bartter's syndrome involves an overlapping set of closely related renal tubular disorders that can be subdivided into at least three clinical phenotypes: (1) the hypercalciuric antenatal Bartter variant; (2) the classic Bartter variant; and (3) the hypocalciuric-hypomagnesemic Gitelman variant. Recent data demonstrate that in several phenotypically indistinguishable cohorts, antenatal Bartter's syndrome is genetically heterogeneous. In these patients, mutations in the genes encoding either the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) or the ATP-regulated potassium channel ROMK (KCNJI) have been identified. A cohort of 20 Costa Rican patients with a congenital syndrome that bears strong similarities to antenatal Bartter's syndrome but also has several distinct features has recently been described. In this cohort, we have identified a predominant mutation that introduces a premature stop in codon W625 of the NKCC2 gene (SCL12A1). This mutant allele is contained on a single common haplotype, suggesting that the majority of antenatal Bartter's syndrome patients in Costa Rica share a single common ancestor.

Severe hyperchloriduria-hyperkaliuria: a new congenital renal tubular abnormality?

A female infant, aged 5 weeks, had metabolic alkalosis associated with severe electrolyte disturbances. In addition to findings typically seen in patients with Bartter syndrome or hyperprostaglandin E syndrome, she had massive urinary excretion of prostaglandins E2 and E-M, normal calcium metabolism, hyperphosphaturia, and severe hyperchloriduria and hyperkaliuria with limited response to indomethacin. These findings may represent a new congenital renal tubular abnormality.