The recent significant increase of cases with Down syndrome in Hungary (1.1/1000 total births between 1973 and 1988, 1.57/1000 between 1989 and 1999 and 1.71/1000 between 2000 and 2006) is explained mainly by the higher proportion of prenatally diagnosed cases. Less important segment of this increase is a somewhat higher proportion of mothers with advanced maternal age and the more complete ascertainment due to the extra effort to reveal all cases in the study. The data of the Hungarian Surveillance of Germinal Mutations based on the Hungarian Congenital Abnormality Registry did not show significant increase in the two forms (pure trisomy 21 as indicator of genom mutations and Robertsonian translocation due to chromosomal mutations) of Down syndrome after the fall-out deposition from Chernobyl in Hungary. In addition the rate of sentinel anomalies (new mutations of autosomal dominant disorders) and unclassified multiple congenital abnormalities (as the most sensitive indicator of environmental hazards) did also not indicate any increase in germinal mutations in Hungary after 1986. The Hungarian Congenital Abnormality Registry detected a very obvious spatial cluster of Down syndrome and other congenital abnormalities in a small Hungarian village, 1989 and 1990. The number of inhabitants in this village was 456 and they had 15 livebirths in 1989 and 1990, and out of these 15 babies, 11 (73.3%) were affected with congenital abnormalities, 4 were affected with Down syndrome. The case-control field study identified trichlorfon used in the fishfarms of the village, as an environmental agent that can induce Down syndrome in very large doses. This observation was confirmed in animal investigations. Thus our finding is an important argument for the necessity and importance of population-based registries of congenital abnormalities. We studied the association between the use of nutritional supplements during the first gestational month and the origin of Down syndrome, and we found a significant protective effect of large doses (about 6 mg/day) of folic acid and iron (150-300 mg/day of ferrous sulfate) for the occurrence of cases with Down syndrome. In general, folic acid and iron were used together, therefore it was difficult to separate these effects due to the limited number of cases and controls. However, the main message of our study is that a pharmacological dose of folic acid and iron supplement appears to have a primary preventive effect for Down syndrome.
|Title of host publication||Handbook of Down Syndrome Research|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||33|
|Publication status||Published - Dec 1 2009|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)