| 1. |
- Leoncini, Emanuele, et al.
(författare)
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Frequency of holoprosencephaly in the International Clearinghouse Birth Defects Surveillance Systems : Searching for population variations.
- 2008
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Ingår i: Birth defects research. Clinical and molecular teratology. - : Wiley. - 1542-0752 .- 1542-0760. ; 82:8, s. 585-591
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Holoprosencephaly (HPE) is a developmental field defect of the brain that results in incomplete separation of the cerebral hemispheres that includes less severe phenotypes, such as arhinencephaly and single median rnaxillary central incisor. Information on the epidemiology of HPE is limited, both because few population-based studies have been reported, and because small Studies must observe a greater number of years in order to accumulate sufficient numbers of births for a reliable estimate. METHODS: We collected data from 2000 through 2004 from 24 of the 46 Birth Defects Registry Members of the International Clearinghouse for Birth Defects Surveillance and Research. This Study is based on more than 7 million births in various areas from North and South America, Europe, and Australia. RESULTS: A total of 963 HPE cases were registered, yielding an overall prevalence of 1.31 per 10,000 births. Because the estimate was heterogeneous, possible causes of variations among populations were analyzed: random variation, Under-reporting and over-reporting bias, variation in proportion of termination of pregnancies among all registered cases and real differences among populations. CONCLUSIONS: The data do not suggest large differences in total prevalence of HPE among the studied Populations that would be useful to generate etiological hypotheses.
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| 2. |
- Leoncini, Emanuele, et al.
(författare)
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How Valid Are the Rates of Down Syndrome Internationally? : Findings from the International Clearinghouse for Birth Defects Surveillance and Research
- 2010
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Ingår i: American Journal of Medical Genetics, Part A. - : Wiley. - 1552-4825 .- 1552-4833. ; 152A:7, s. 1670-1680
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Tidskriftsartikel (refereegranskat)abstract
- Rates of Down syndrome (DS) show considerable international variation, but a systematic assessment of this variation is lacking. The goal of this study was to develop and test a method to assess the validity of DS rates in surveillance programs, as an indicator of quality of ascertainment. The proposed method compares the observed number of cases with DS (livebirths plus elective pregnancy terminations, adjusted for spontaneous fetal losses that would have occurred if the pregnancy had been allowed to continue) in each single year of maternal age, with the expected number of cases based on the best-published data on rates by year of maternal age. To test this method we used data from birth years 2000 to 2005 from 32 surveillance programs of the International Clearinghouse for Birth Defects Surveillance and Research. We computed the adjusted observed versus expected ratio (aOE) of DS birth prevalence among women 25-44 years old. The aOE ratio was close to unity in 13 programs (the 95% confidence interval included 1), above 1 in 2 programs and below 1 in 18 programs (P < 0.05). These findings suggest that DS rates internationally can be evaluated simply and systematically, and underscores how adjusting for spontaneous fetal loss is crucial and feasible. The aOE ratio can help better interpret and compare the reported rates, measure the degree of under- or over-registration, and promote quality improvement in surveillance programs that will ultimately provide better data for research, service planning, and public health programs.
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| 3. |
- Mastroiacovo, Pierpaolo, et al.
(författare)
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Gastroschisis and associated defects : an international study
- 2007
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Ingår i: American Journal of Medical Genetics, Part A. - : Wiley. - 1552-4825 .- 1552-4833. ; 143A:7, s. 660-671
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Tidskriftsartikel (refereegranskat)abstract
- Our objective was to evaluate the frequency and type of malformations associated with gastroschisis in a large pool of international data, to identify malformation patterns, and to evaluate the role of maternal age in non-isolated cases. Case-by-case information from 24 registries, all members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), were evaluated. After the exclusion of other abdominal wall defects cases were classified as: (a) isolated; (b) recognizable syndrome, chromosomal or not; (c) multiple congenital anomalies (MCA). Our results showed that out of 3,322 total cases 469 non-isolated cases were registered (14.1%): 41 chromosomal syndromes, 24 other syndromes, and 404 MCA. Among MCA four groups of anomalies were most frequent: CNS (4.5%), cardio-vascular (2.5%), limb (2.2%), and kidney anomalies (1.9%). No similar patterns emerged except two patterns resembling limb-body wall complex and OEIS. In both of them the gastroschisis could be however misclassified. Chromosomal trisomies and possibly non-syndromic MCA are associated with an older maternal age more than isolated cases. On consideration of our data and the most valid studies published in the literature, the best estimate of the proportion of gastroschisis associated with major unrelated defects is about 10%, with a few cases associated to recognizable syndromes. Recognized syndromes with gastroschisis seem to be so exceptional that the well documented and validated cases are worth being published as interesting case report. An appropriate case definition in etiological studies should include only isolated gastroschisis after an appropriate definition of isolated and non-isolated cases and a thorough case-by-case review.
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