This new test under development is based upon microarray-based comparative genomic hybridization (array CGH).
All fetal cells should have complete copies of maternal and paternal genomes. The test compares regions of fetal DNA that deviate from this "pattern" due to either too much or too little DNA, alterations reflect regions of the genome that are either copied or deleted. These genetic changes may therefore cause disease. (More? see recent article Nature 438, 733-734 (8 December 2005) Fetal genetic testing: Screen test)
Microarrays are a new technique that allows a large number of different genetic sequences to be arrayed on a slide which can then be used to identify specific sequences in an unknown mix of either DNA or RNA. This technique required the development of DNA synthetic techniques and microprocessor controlled robotics for array design and has been used extensively in cell biology.
What is an array? "to place in an orderly arrangement" Think of a hairbrush with each "hair" dipped in individual coloured inks and applied to paper. Each "hair" would makes an individual coloured "spot". Now consider instead of ink, if each hair had a different piece of DNA then a specific pattern is generated.
(More? UNSW Cell Biology Microarray)
Check E. Fetal genetic testing: Screen test. Nature. 2005 Dec 8;438(7069):733-4.
Vissers LE, Veltman JA, van Kessel AG, Brunner HG. Identification of disease genes by whole genome CGH arrays. Hum Mol Genet. 2005 Oct 15;14 Spec No. 2:R215-23.
Rickman L, Fiegler H, Carter NP, Bobrow M. Prenatal diagnosis by array-CGH. Eur J Med Genet. 2005 Jul-Sep;48(3):232-40.
Tempest HG, Griffin DK. The cytogenetics of preimplantation human development: insights provided by traditional and novel techniques. Chromosoma. 2005 Sep;114(4):295-9. Epub 2005 Oct 15. Review.
Barrett MT, Scheffer A, Ben-Dor A, Sampas N, Lipson D, Kincaid R, Tsang P, Curry B, Baird K, Meltzer PS, Yakhini Z, Bruhn L, Laderman S. Comparative genomic hybridization using oligonucleotide microarrays and total genomic DNA. Proc Natl Acad Sci U S A. 2004 Dec 21;101(51):17765-70. Epub 2004 Dec 10. PNAS
1988 recommendations for neonates be assessed for follow-up care under the following conditions.
(see the NHMRC WWW Page)
Each section of the notes covering early development and specific systems contain references to specific abnormalities (on Page 2 of each notes section). The best source for Australian statistical data is the Australian Institute of Health and Welfare National Perinatal Statistics Unit, UNSW which publishes "Congenital Malformations Australia" every 2 years. Be aware that some congenital abnormalities, by their nature, affect multiple systems. In the USA, the Center for Disease Control (CDC) keeps and publishes relevant statistical information. A very difficult issue in abnormal development are the many different Ethical implications.
This current page is a link to Normal and Abnormal Development and Population Data.
Look at types of Abnormal Development that can occur during development.
Alternatively, look at normal development. Development Notes
For those wanting to see dynamic processes of development (and have a reasonably quick connection) then the Movies pages are good for watching changes occur.
The study of human development has relied extensively on studying the process in other model animals. For those wanting to see the process of development in other species then the other embryos pages are a good start.
Home Page
Embryo stages
Fetal Dev
Dev Notes 1
Dev Notes 2
System Notes
Acknowledgements
Abnormal
Major System Abnormalities
Prenatal Diagnosis
Comparative Genomic Hybridization
Movies
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Class Notes
Serial Images
K12 Students
Abnormal
Embryology in the News
Histology
Site Map
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UNSW Cell Biology
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Dev Biol (Gilbert)
How do I find out if everything is OK with my developing baby and what are the tests that doctors carry out?
Prenatal diagnosis is based the various types of tests that can be carried out to inform parents and clinicians. With the rising age of mothers in Australia and new knowledge about family genetic history these tools are useful in helping clinicians check the developing fetus. Note that some tests, like ultrasound, are relatively non-invasive, informative, and carried out in many suburban clinics.
See also the Prenatal Diagnosis page NSW Pamphlet Checking your baby's health before birth.
Please email Dr Mark Hill if you wish to make a comment about this current project.