Severe polyhydramnios as neonatal presentation of Bartter's syndrome type IV / Polihidrâmnios grave como manifestação neonatal da síndrome de Bartter tipo IV

Abstract Introduction: Bartter's syndrome comprises a heterogeneous group of inherited salt-losing tubulopathies. There are two forms of clinical presentation: classical and neonatal, the most severe type. Types I and II account for most of the neonatal cases. Types III and V are usually less severe. Characteristically Bartter's syndrome type IV is a saltlosing nephropathy with mild to severe neonatal symptoms, with a specific feature - sensorineural deafness. Bartter's syndrome type IV is the least common of all recessive types of the disease. Description: the first reported case of a Portuguese child with neurosensorial deafness, polyuria, polydipsia and failure to thrive, born prematurely due to severe polyhydramnios, with the G47R mutation in the BSND gene that causes Bartter's syndrome type IV. Discussion: there are few published cases of BS type IV due to this mutation and those reported mostly have moderate clinical manifestations which begin later in life. The poor phenotype-genotype relationship combined with the rarity of this syndrome usually precludes an antenatal diagnosis. In the presence of a severe polyhydramnios case, with no fetal malformation detected, normal karyotype and after maternal disease exclusion, autosomal recessive diseases, including tubulopathies, should always be suspected.

Resumo Introdução: a síndrome de Bartter inclui um grupo heterogéneo de tubulopatias hereditárias perdedoras de sal. Existem duas formas de apresentação clínica: clássica e neonatal, a forma mais grave. Os tipo I e II representam a maioria dos casos neonatais. Os tipos III e V são geralmente menos graves. Caracteristicamente, a síndrome de Bartter tipo IV é uma nefropatia perdedora de sal com sintomas neonatais ligeiros a graves, com um aspeto especí- fico - surdez neurossensorial. A síndrome de Bartter tipo IV é o tipo menos comum das formas recessivas da doença. Descrição: relatamos o primeiro caso de uma criança portuguesa, com surdez neurossensorial, poliúria, polidipsia e restrição de crescimento, nascida prematuramente devido a polihidrâmnios grave, homozigótica para a mutação G47R do gene BSND, responsável pela síndrome de Bartter tipo IV. Discussão: são raros os casos publicados sobre síndrome de Bartter tipo IV atribuída a esta mutação, e a maioria referem-se a diagnósticos mais tardios, com manifestações clínicas ligeiras. A fraca correlação fenótipo-genótipo combinada com a raridade desta síndrome tornam o diagnóstico pré-natal desafiante. Perante um caso de polihidrâmnios grave em um feto sem malformações aparentes, cariótipo normal e após exclusão de patologia materna, as doenças autossómicas recessivas, incluindo as tubulopatias, devem ser sempre consideradas.

Unraveling the pathogenesis of ARX polyalanine tract variants using a clinical and molecular interfacing approach.

The Aristaless-related homeobox (ARX) gene is implicated in intellectual disability with the most frequent pathogenic mutations leading to expansions of the first two polyalanine tracts. Here, we describe analysis of the ARX gene outlining the approaches in the Australian and Portuguese setting, using an integrated clinical and molecular strategy. We report variants in the ARX gene detected in 19 patients belonging to 17 families. Seven pathogenic variants, being expansion mutations in both polyalanine tract 1 and tract 2, were identifyed, including a novel mutation in polyalanine tract 1 that expands the first tract to 20 alanines. This precise number of alanines is sufficient to cause pathogenicity when expanded in polyalanine tract 2. Five cases presented a probably non-pathogenic variant, including the novel HGVS: c.441_455del, classified as unlikely disease causing, consistent with reports that suggest that in frame deletions in polyalanine stretches of ARX rarely cause intellectual disability. In addition, we identified five cases with a variant of unclear pathogenic significance. Owing to the inconsistent ARX variants description, publications were reviewed and ARX variant classifications were standardized and detailed unambiguously according to recommendations of the Human Genome Variation Society. In the absence of a pathognomonic clinical feature, we propose that molecular analysis of the ARX gene should be included in routine diagnostic practice in individuals with either nonsyndromic or syndromic intellectual disability. A definitive diagnosis of ARX-related disorders is crucial for an adequate clinical follow-up and accurate genetic counseling of at-risk family members.

Genotyping of gastroenteric viruses in hospitalised children: first report of norovirus GII.21 in Brazil

This retrospective study (April-September 2003) was designed to investigate the roles of the main viruses responsible for cases of acute infantile gastroenteritis in hospitalised children up to two years of age. The viruses were identified in 64.7% (88/136) of the cases and the detection rates of rotavirus A (RVA), norovirus (NoV) and astrovirus were 41.9% (57/136), 30.3% (24/79) and 12.7% (7/55), respectively. RVA and NoV were detected in 20 of the 24 reported nosocomial infection cases. This study identified the first circulation of the genotype NoV GII.21 in Brazil and highlights the need to establish differential diagnoses through active laboratorial surveillance.

Genotyping of gastroenteric viruses in hospitalised children: first report of norovirus GII.21 in Brazil.

This retrospective study (April-September 2003) was designed to investigate the roles of the main viruses responsible for cases of acute infantile gastroenteritis in hospitalised children up to two years of age. The viruses were identified in 64.7% (88/136) of the cases and the detection rates of rotavirus A (RVA), norovirus (NoV) and astrovirus were 41.9% (57/136), 30.3% (24/79) and 12.7% (7/55), respectively. RVA and NoV were detected in 20 of the 24 reported nosocomial infection cases. This study identified the first circulation of the genotype NoV GII.21 in Brazil and highlights the need to establish differential diagnoses through active laboratorial surveillance.