DETERMINAÇÃO DE TETRACICLINAS EM LEITE POR CROMATOGRAFIA DE CAMADA FINA

As tetraciclinas são compostos antibacterianos utilizados em bovinos de leite para tratamento de doenças infecciosas, como a mastite, mas também como aditivos em ração animal. O uso das tetraciclinas pode conduzir à presença de resíduos destes fármacos no leite, principalmente se não forem utilizados de acordo com as indicações, nem respeitado o período mínimo de eliminação dos antibióticos pelo leite. A presença de resíduos de antibióticos no leite interfere no processo industrial dos seus derivados, podendo inviabilizar a produção destes e, consequentemente, causar igualmente prejuízos económicos, como por exemplo, pela inibição de fermentos lácticos que são culturas de microorganismos utilizados na produção de iogurtes, queijos e outros produtos lácteos. Os resíduos de antibióticos no leite de consumo podem representar riscos à saúde humana, podendo causar reacções alérgicas em indivíduos sensíveis ou ter um efeito adverso na flora intestinal humana, prejudicando a sua acção protectora local, além de propiciar a selecção de populações bacterianas resistentes. (Denobile & Nascimento, 2004

Mutations in the MECP2 gene are not a major cause of Rett syndrome-like or related neurodevelopmental phenotype in male patients

Rett syndrome is a genetic neurodevelopmental disorder that affects mainly girls, but mutations in the causative MECP2 gene have also been identified in boys with classic Rett syndrome and Rett syndrome-like phenotypes. We have studied a group of 28 boys with a neurodevelopmental disorder, 13 of which with a Rett syndrome-like phenotype; the patients had diverse clinical presentations that included perturbations of the autistic spectrum, microcephaly, mental retardation, manual stereotypies, and epilepsy. We analyzed the complete coding region of the MECP2 gene, including the detection of large rearrangements, and we did not detect any pathogenic mutations in the MECP2 gene in these patients, in whom the genetic basis of disease remained unidentified. Thus, additional genes should be screened in this group of patients.Moónica Santos was supported by Fundação para a Ciência e Tecnologia (FCT, Portugal) with the PhD fellowship SFRH/BD/9111/2002 and the postdoc fellowship SFRH/BPD/28555/2006. Research in Rett syndrome is supported by FSE/FEDER and FCT, Grant POCTI 41416/2001

Germline MUTYH (MYH) mutations in portuguese individuals with multiple colorectal adenomas

Germinal mutations in the base excision repair (BER) gene MUTYH (MYH) have recently been described in association with predisposition to multiple colorectal adenomas and cancer. In contrast to the classic dominant condition of familial adenomatous polyposis (FAP) due to germinal mutations in the APC gene, the MYH polyposis is an autosomal recessive disease. The identification of individuals affected by MYH polyposis brings new and important implications for the diagnostic, screening, genetic counseling, follow up and therapeutic options in these patients. In this study, screening for germinal mutations in the MYH gene was performed in 53 Portuguese individuals with multiple colorectal adenomas or classic adenomatous polyposis, in whom no mutation had been identified in the APC gene. The results revealed the presence of biallelic germline MYH mutations in 21 patients. In addition, we here report 3 mutations (c.340T>C [p.Y114H]; c.503G>A [p.R168H]; and c.1186_1187insGG [p.E396fsX437]) which, to our knowledge, have not been previously described. © 2004 Wiley-Liss, Incinfo:eu-repo/semantics/publishedVersio

Genetic diagnosis of X-linked dominant hypophosphatemic rickets in a cohort study: Tubular reabsorption of phosphate and 1,25(OH)2D serum levels are associated with PHEX mutation type

<p>Abstract</p> <p>Background</p> <p>Genetic Hypophosphatemic Rickets (HR) is a group of diseases characterized by renal phosphate wasting with inappropriately low or normal 1,25-dihydroxyvitamin D₃(1,25(OH)₂D) serum levels. The most common form of HR is X-linked dominant HR (XLHR) which is caused by inactivating mutations in the <it>PHEX </it>gene. The purpose of this study was to perform genetic diagnosis in a cohort of patients with clinical diagnosis of HR, to perform genotype-phenotype correlations of those patients and to compare our data with other HR cohort studies.</p> <p>Methods</p> <p>Forty three affected individuals from 36 non related families were analyzed. For the genetic analysis, the <it>PHEX </it>gene was sequenced in all of the patients and in 13 cases the study was complemented by mRNA sequencing and Multiple Ligation Probe Assay. For the genotype-phenotype correlation study, the clinical and biochemical phenotype of the patients was compared with the type of mutation, which was grouped into clearly deleterious or likely causative, using the Mann-Whitney and Fisher's exact test.</p> <p>Results</p> <p>Mutations in the <it>PHEX </it>gene were identified in all the patients thus confirming an XLHR. Thirty four different mutations were found distributed throughout the gene with higher density at the 3' end. The majority of the mutations were novel (69.4%), most of them resulted in a truncated PHEX protein (83.3%) and were family specific (88.9%). Tubular reabsorption of phosphate (TRP) and 1,25(OH)₂D serum levels were significantly lower in patients carrying clearly deleterious mutations than in patients carrying likely causative ones (61.39 ± 19.76 vs. 80.14 ± 8.80%, p = 0.028 and 40.93 ± 30.73 vs. 78.46 ± 36.27 pg/ml, p = 0.013).</p> <p>Conclusions</p> <p><it>PHEX </it>gene mutations were found in all the HR cases analyzed, which was in contrast with other cohort studies. Patients with clearly deleterious <it>PHEX </it>mutations had lower TRP and 1,25(OH)₂D levels suggesting that the <it>PHEX </it>type of mutation might predict the XLHR phenotype severity.</p

Síndrome de Kabuki: Caracterização de 16 doentes portugueses

A Síndrome de Kabuki (SK, OMIM-147920), descrita pela primeira vez por Kuroki e Niikawa em 1981, caracteriza-se por fácies típico, défice cognitivo ligeiro a moderado, presença de polpas dos dedos com aspecto fetal, baixa estatura, e anomalias esqueléticas. O espectro clínico inclui anomalias em outros órgãos e sistemas, sendo frequentes as anomalias dentárias, a hiperlaxidez articular, a susceptibilidade aumentada às infecções na infância e a telarca precoce. Existem mais de 350 casos publicados na literatura; porém, pensa-se que seja uma situação sub-diagnosticada. A etiologia permanece desconhecida. A maioria dos casos é esporádica, com hereditariedade autossómica dominante sugerida nalgumas famílias.Apresentam-se as características clínicas de uma série de 16 doentes com SK, 9 do sexo masculino e 7 do sexo feminino, de idades compreendidas entre os 14 meses e os 24 anos. Os achados clínicos foram consistentes com a literatura, e foi encontrado um número significativo de anomalias oftalmológicas, cardiovasculares, do sistema nervoso central, e urogenitais na série estudada. A incidência de baixa estatura foi ligeiramente inferior ao anteriormente publicado. Referimos algumas patologias não descritas previamente em doentes com SK: feocromocitoma e acidente vascular cerebral. O objectivo é divulgar as principais características da Síndrome de Kabuki, com as quais os pediatras e outros técnicos de saúde infantil devem estar familiarizados

Pseudoacondroplasia — Dois Casos Clínicos em Idades Distintas

As displasias ósseas, dentro das doenças genéticas, são das que colocam mais dificuldades diagnósticas. Se por um lado as características distintivas entre os vários tipos são por vezes difíceis de reconhecer e valorizar, por outro, pode existir uma variabilidade fenotípica importante dentro da mesma entidade.A pseudoacondroplasia (PSACH) é uma displasia óssea de hereditariedade autossómica dominante, com envolvimento da coluna, metáfises e epífises dos ossos longos. É causada por uma mutação no gene COMP (cartilage oligomeric matrix protein), localizado no braço curto do cromossoma 19.Apresentamos dois casos clínicos desta entidade em que o diagnóstico foi efectuado em idades distintas. As diferentes formas de apresentação exemplificam a heterogeneidade clínica desta situação

Defective proteolytic processing of fibrillar procollagens and prodecorin due to biallelic BMP1 mutations results in a severe, progressive form of osteogenesis imperfecta

Whereas the vast majority of osteogenesis imperfecta (OI) is caused by autosomal dominant defects in the genes encoding type I procollagen, mutations in a myriad of genes affecting type I procollagen biosynthesis or bone formation and homeostasis have now been associated with rare autosomal recessive OI forms. Recently, homozygous or compound heterozygous mutations in BMP1, encoding the metalloproteases bone morphogenetic protein-1 (BMP1) and its longer isoform mammalian Tolloid (mTLD), were identified in 5 children with a severe autosomal recessive form of OI and in 4 individuals with mild to moderate bone fragility. BMP1/ mTLD functions as the procollagen carboxy-(C)-proteinase for types I to III procollagen but was also suggested to participate in amino-(N)-propeptide cleavage of types V and XI procollagens and in proteolytic trimming of other extracellular matrix (ECM) substrates. We report the phenotypic characteristics and natural history of 4 adults with severe, progressive OI characterized by numerous fractures, short stature with rhizomelic shortening, and deformity of the limbs and variable kyphoscoliosis, in whom we identified novel biallelic missense and frameshift mutations in BMP1. We show that BMP1/mTLD-deficiency in humans not only results in delayed cleavage of the type I procollagen C-propeptide but also hampers the processing of the small leucine-rich proteoglycan prodecorin, a regulator of collagen fibrillogenesis. Immunofluorescent staining of types I and V collagen and transmission electron microscopy of the dermis show impaired assembly of heterotypic type I/V collagen fibrils in the ECM. Our study thus highlights the severe and progressive nature of BMP1-associated OI in adults and broadens insights into the functional consequences of BMP1/mTLD-deficiency on ECM organization.Methusalem Grant 08/01M01108; Grant G.0171.0

Koolen-de Vries syndrome – National Case Series with clinical and molecular characterization

Introduction: Koolen-de Vries Syndrome (KdVS) is a rare genetic condition, caused by a 17q21.31 microdeletion, or a pathogenic variant in KANSL1 gene. The clinical picture includes developmental delay (DD)/intellectual disability (ID) with expressive language particularly impaired, dysmorphisms, neonatal hypotonia, and friendly behaviour. Aim: To characterize at the molecular and clinical levels all patients in Portugal diagnosed with KdVS.N/

Loss of function of KIAA2022 causes mild to severe intellectual disability with an autism spectrum disorder and impairs neurite outgrowth

International audienceExistence of a discrete new X-linked intellectual disability (XLID) syndrome due to KIAA2022 deficiency was questioned by disruption of KIAA2022 by an X-chromosome pericentric inversion in a XLID family we reported in 2004. Three additional families with likely pathogenic KIAA2022 mutations were discovered within the frame of systematic parallel sequencing of familial cases of XLID or in the context of routine array-CGH evaluation of sporadic intellectual deficiency (ID) cases. The c.186delC and c.3597dupA KIAA2022 truncating mutations were identified by X-chromosome exome sequencing, while array CGH discovered a 70 kb microduplication encompassing KIAA2022 exon 1 in the third family. This duplication decreased KIAA2022 mRNA level in patients' lymphocytes by 60%. Detailed clinical examination of all patients, including the two initially reported, indicated moderate-to-severe ID with autistic features, strabismus in all patients, with no specific dysmorphic features other than a round face in infancy and no structural brain abnormalities on magnetic resonance imaging (MRI). Interestingly, the patient with decreased KIAA2022 expression had only mild ID with severe language delay and repetitive behaviors falling in the range of an autism spectrum disorder (ASD). Since little is known about KIAA2022 function, we conducted morphometric studies in cultured rat hippocampal neurons. We found that siRNA-mediated KIAA2022 knockdown resulted in marked impairment in neurite outgrowth including both the dendrites and the axons, suggesting a major role for KIAA2022 in neuron development and brain function

BRF1 mutations alter RNA polymerase III-dependent transcription and cause neurodevelopmental anomalies

RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of bif1 in zebraflsh embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III-related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development