Boletín del ECEMC: Revista de Dismorfología y Epidemiología - 2007 - Serie V Nº 6
http://hdl.handle.net/20.500.12105/5711
2024-03-29T00:47:40ZBoletín del ECEMC: Revista de Dismorfología y Epidemiología 2007; Serie V Nº 6
http://hdl.handle.net/20.500.12105/14033
Sumario de Boletín del ECEMC: Revista de Dismorfología y Epidemiología 2007; Serie V Nº 6
2007-10-01T00:00:00ZBoletín del ECEMC: Revista de Dismorfología y Epidemiología - 2007 - Serie V Nº 6
http://hdl.handle.net/20.500.12105/14032
Número completo de: Boletín del ECEMC: Revista de Dismorfología y Epidemiología - 2007 - Serie V Nº 6
2007-10-01T00:00:00ZModificación del Comité Editorial
http://hdl.handle.net/20.500.12105/14031
2007-10-01T00:00:00ZReflexiones sobre las Bases Físico-Matemáticas de los Sistemas Biológicos y del Genoma
http://hdl.handle.net/20.500.12105/14030
2007-10-01T00:00:00ZSíndrome de Smith-Lemli-Opitz
http://hdl.handle.net/20.500.12105/14029
The Smith-Lemli-Opitz syndrome is an autosomal recessive multiple congenital anomaly/mental retardation pattern caused by an inborn error of cholesterol metabolism. Deficient cholesterol synthesis is caused by inherited mutations of 7-dehydrocholesterol reductase gene, that catalyzes the final step of the pathway: the conversion of 7-dehydrocholesterol to cholesterol. To date, more than 125 different mutations have been identified and more than 750 patients have been reported with an extremely broad clinical spectrum. This paper describes two patients with a neonatal diagnosis and reviews the syndrome with special insights into genetics, pathogenesis, diagnosis, prenatal included, and treatment
2007-10-01T00:00:00ZDeleción parcial 5p y duplicación parcial 5q derivadas de una inversión pericéntrica familiar
http://hdl.handle.net/20.500.12105/14028
During the meiotic process, most of the structural balanced chromosome alterations will affect either the specific chromosome pairing, or the chromosome and cromatides segregation, due to the number and type of chiasmata of the chromosomes implicated in those balanced rearrangements. Thus, the major clinical significance for normal carriers is the risk of transmition to their offspring unbalanced derivative. Here we present a malformed newborn infant with an abnormal chromosome 5 consisting in a partial deletion 5p and a partial duplication 5q. This abnormal chromosome 5 was a recombinant chromosome derived from a large paternal pericentric inversion. The cytogenetic study of the family showed that there were some other members who were carriers of the same balanced inversion. The clinical features of this patient are a mixture of some anomalies clearly related to the 5p deletion or "Cri-du-Chat" syndrome, like the crying and facial appearance, together with other that are describe on patients with 5q duplication, like the cardiac malformation. Nevertheless, he also shows some congenital defects as preauricular tags and anal atresia that, as for as we know, have not been previously described in patients with a similar chromosomal alteration. A literature review was performed of the genes localize at the chromosome regions involve in the inversion, in an effort to establish a relation with the patient phenotype.
2007-10-01T00:00:00ZAspectos clínicos y distribución etiológica de los recién nacidos con defectos congénitos registrados en el ECEMC
http://hdl.handle.net/20.500.12105/14027
An epidemiological analysis of the main clinical aspects of the infants with congenital defects registered by the ECEMC (Spanish Collaborative Study of Congenital Malformations) between 1980 and 2006, has been performed. Among a total of 2,254,439 newborn surveyed, 35,246 (1.56%), had congenital defects detected during the first 3 days of life. This group of malformed infants was distributed according to their clinical presentation as isolated (74.01%), multiply malformed (13.43%), and syndromes (12.56%). The etiologic distribution of infants with congenital anomalies in the ECEMC showed a 20.42% of genetic cause, 21.03% multifactorial, 1.22% produced by environmental cause, and in the remaining 57.33% the etiology of the defects was unknown. The secular distribution of the 3 main groups of clinical presentation (isolated, multiply malformed and syndromes) was studied and all of them showed a decreasing trend along the years, probably as a consequence of the impact of the interruption of pregnancy of some affected fetuses. The different types of syndromes and their minimal frequency values were also presented separated by type of cause.
2007-10-01T00:00:00ZSíndromes muy poco frecuentes
http://hdl.handle.net/20.500.12105/14026
The aim of this chapter is to summarize updated knowledge about the clinical characteristics, etiology, genetic and molecular aspects, as well as mechanisms involved in syndromes having very low frequency, in order to promote their better recognition. During the last five years, a total of 30 syndromes have been published in this chapter of the Boletín del ECEMC. This issue includes the following selected syndromes: Crouzon, Pfeiffer, Apert, Saethre-Chotzen, Carpenter and Muenke. All share craniosynostosis as the main clinical feature but also present with other birth defects, the most important being limb malformations, specially syndactyly and polydactyly. Over 100 syndromes with craniosynostosis have been described, usually involving multiple sutures, and several of them are associated with limb malformations. The clinical overlapping between those syndromes makes difficult to perform a neonatal diagnosis, based on their clinical findings. However, molecular genetic testing, specifically of the FRGR1-3 and TWIST1 genes, could help to establish the diagnosis of some of them. Early diagnosis is important for establishing the most suitable treatment for each patient, as well as to offer an accurate genetic counselling and the possibility of preimplantational and/or prenatal diagnosis.
2007-10-01T00:00:00ZVitamina A y embarazo: Revisión de la literatura y estimación del riesgo teratogénico
http://hdl.handle.net/20.500.12105/14025
Vitamin A plays a key role in many essential biological processes, such as the embryonic development, regulation of proliferation and diferentiation of many cell types. The present article reviews the biochemistry, metabolism and mode of action of retinoides (including vitamin A), as well as their role in the embryo development and their teratogenic effect on animal and human beings.
2007-10-01T00:00:00ZVigilancia epidemiológica de anomalías congénitas en España: Análisis de los datos del ECEMC en el período 1980-2006
http://hdl.handle.net/20.500.12105/14024
This chapter summarizes the main results of the current epidemiological surveillance of congenital anomalies performed in the Spanish Collaborative Study of Congenital Malformations (ECEMC). This is a research programme developed as a hospital-based case-control study and surveillance system, aimed at investigating the characteristics and causes of congenital defects. It started in 1976, with a common methodology for all the participants in the programme. According to the most recent data, it covers 22.96% of births in Spain. It has been found that the general tendency of the neonatal frequency of congenital defects in Spain is decreasing since the passing, in 1985, of the law allowing voluntary termination of pregnancy (TOP) after the detection of fetal anomalies. The frequency has fallen from the base frequency registered in 1980-1985 (2.22%) up to 1.16% in the year 2006. This general tendency has also been proven for most of the defects under systematic surveillance in the ECEMC. The most noticeable decrease has been observed for the global frequency of Down syndrome, and this decrease is even more pronounced for the oldest maternal ages, as a result of the impact of TOPs. In the analyses by Autonomous Regions (look at the map in Figure 1 to see their location), there was only a statistically significant increase of the global frequency, in Extremadura, that can be attributable to the improvements in the neonatal and obstetrical care in this region, not being necessary to move deliveries at risk to other Autonomous Regions. Regarding the frequency of specific defects, there have been increases in the frequency of esophageal atresia/stenosis in Castilla-La Mancha, anal-rectal atresia/stenosis in Tenerife (Islas Canarias), gastroschisis also in Tenerife, and hypospadias in Castilla y León. For the first two defects, after excluding cases with syndromes with multiple congenital anomalies, they lost statistical significance. For gastroschisis in Tenerife, there were some risk factors among the cases (young maternal age, change in paternity of the different infants of the mother) that could account for the cluster, although it will be closely followed up. For hypospadias, there has not been found any common denominator in the cases that could be considered as the cause of the cluster in Castilla y León, that will also be closely monitored. In conclusion, the ECEMC system of epidemiological surveillance has demonstrated being effective in determining the birth frequency of congenital defects in Spain, its secular trend and geographical distribution, as well as for detecting several increases in the frequency of some congenital defects, leading to a close monitoring of the clusters, which is important for determining their causes and for the prevention of congenital defects, apart from their usefulness in the planning of health and social resources.
2007-10-01T00:00:00ZEl Genoma Humano. Un Sistema Altamente Complejo
http://hdl.handle.net/20.500.12105/14023
Since the completion of the sequence of the human genome, knowledge of the structure and function of DNA is growing dramatically. However, at the same time, studies are showing an impressive complexity in the structural and functional aspects of DNA. One of the first findings was the identification of frequent DNA variants known as Single Nucleotide Polymorphisms (SNP). More recently, and particularly since 2004, a high degree of fine scale structural variations in the human genome are being identified, which at present are globally called Copy Number Variations/variants (CNVs). As these CNVs are quite frequent, they have been considered polymorphisms, and are responsible for a greater individual variability than SNPs, with a genetic variation estimated in 1/800 bp, while the SNPs vary in 1/1,200 bp. The CNVs are classified into those altering the number of DNA copies, such as insertions, deletions, and duplications, and those affecting its position (translocations) or its orientation (inversions). In addition, according to the number of repeat copies and, therefore, size, CNVs are classified as (Table 2): Large-scale Copy Variations (LCV), Intermediate-sized Structural Variants (ISV) and Low Copy Repeats (LCR). Although there are evidences that the CNVs, even including genes, do not necessarily have adverse effects on individuals who carry them, they may have adverse consequences even when they only include non-coding DNA (ncDNA). Some of them could alter meiotic chromosome pairing giving rise to gametes carrying unbalanced chromosome constitutions. In addition, there are several publications showing that some CNVs are related with malformations and syndromes (holoprosencephaly19, Peters anomaly24, Townes-Bröcks syndrome25, Cleidocranial dysplasia19, Campomelic dysplasia21-23, and other skeletal dysplasias26), that are due to position-effect and other types of effects such as alteration of gene dosage or the presence of unbalanced chromosomal alterations. In 2006, Redon et al.9, published a map with the global variation in copy numbers in each of the 46 chromosomes of the human genome. These results parallel the identification of new transcriptional processes, that have also increased since the recognition that the number of genes in the human genome is slightly more than 1/4 of previous estimates. Several studies have recently shown that nearly the whole human genome is transcribed, and that about 98% of the human genome that is transcribed represents non-coding RNA (ncRNA). This has led to many questions regarding their functional meaning, its relationship with RNA coding proteins, and its implications in the regulation and structural organization of the genome. But, at the same time, there has been an increasing knowledge on the function of different ncRNAs that shows an intricate pattern of interrelations and imbrications. Functionally, these ncRNAs are separated into two groups. One includes the housekeeping ncRNAs that is necessary for the normal function of the cells, such as RNA of transference, nuclear RNAs, ribosomal RNAs, etc. The other group includes the ncRNAs regulators that are expressed in embryonic development during cell differentiation, or as response to different stimuli, and can affect the expression of other genes. Among these are the riboswitches and others that participate in regulating gene expression and transcription and post-transcription processes such as microRNA (miRNA) and interference RNA (iRNA). Recent studies have observed that miRNA can use the interference pathway to activate genes, which is a surprising finding41-42. Structural and functional investigations on the different ncRNAs have shown that several of them are related with some human diseases and defects (Table 4). In addition, this year, studies on introns, which are a source of miRNA in different animals (D. melanogaster, C. elegans), have identified a different class of miRNA precursors, called "mirtrons" whose function is yet unknown. However, recent studies have suggested that they may function in the regulatory biological network, and that they may also exist in other species43-44. The recent publication of the results of the pilot study of the ENCODE Project (ENCcyclopedia Of DNA Elements)27-28, has offered a highly complex structural and functional view of the human genome and in the structure of RNAs36, as well as the implications in the alternative transcription (splicing). In relation with this last process, the current results on the function of the alternative proteins suggest that it may not be exactly as previously considered37. All these findings have led to the revision of previous concepts, starting by the "dogma" of the gene definition. The proposed definition, which represents a good example of the complexity of the human genome, is as follows: The gene is a union of genomic sequences encoding a coherent set of potentially overlapping functional products.30 This article presents a simplified general review of the most recent findings summarized above, reviewing: a) the structural variations of DNA and functional elements of the human genome, and b) the types and function of different RNAs. Finally, as a reflection, it is clear that the DNA code is much more than the lecture of the combination of the four bases (adenine, guanine, thymine, and cytosine), and although our knowledge of their structure and function it is still very small, its high level of complexity is becoming increasingly evident. New information shows multiple and complex frameworks of different functional networks, whose products are not the sum of their components, but "emergent behaviors" in relationship with the other parts of the whole system, although its laws are still unknown. All these aspects are concordant with the characteristics of the so called "complex systems or chaotic systems". These, as the chaos theory postulates, do not have absence of order or causality, but a particular interrelationship that gives rise to new levels that are subject to their own emergent rules. Thus, it is possible that the rules that command the human genome are not physically or mathematically different from those that conduct the "Complex systems" regulating nature.
2007-10-01T00:00:00ZResultados de la actividad de los Servicios de Información sobre Teratógenos (SITTE y SITE) durante el año 2006 y análisis de la edad materna y del número de embarazos planeados
http://hdl.handle.net/20.500.12105/14022
We present a summary of the activity of the two Teratology Information Services: SITTE (for health professionals) and SITE (for the general population) during 2006. We also include a comparative analysis on maternal age and number of planned pregnancies between the population of mothers who called to SITE and the mothers of the ECEMC's controls (as a representative group of the general population). The total number of calls received in both services was 4,876 (898 and 3,978 from SITTE and SITE respectively).
2007-10-01T00:00:00ZPosters presentados en la XXX Reunión del ECEMC
http://hdl.handle.net/20.500.12105/14021
2007-10-01T00:00:00Z