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| CLINICAL QUERIES |
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| Year : 2017 | Volume
: 15
| Issue : 2 | Page : 85-86 |
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Clinical questions: Responses to clinical queries from readers: Down's syndrome
Santosh Benjamin
Associate Professor, Department of Obstetrics and Gynecology, Christian Medical College, Vellore, Tamil Nadu, India
| Date of Web Publication | 18-May-2017 |
Correspondence Address:
Santosh Benjamin
Associate Professor, Department of Obstetrics and Gynecology, Christian Medical College, Vellore, Tamil Nadu
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0973-4651.206543
How to cite this article:
Benjamin S. Clinical questions: Responses to clinical queries from readers: Down's syndrome. Curr Med Issues 2017;15:85-6 |
Question 2
As a primary care doctor, how can I assess the possibility of “Down's Syndrome” in a developing fetus in a primigravida above 35 years of age. I want to know the basic tests.
Down's syndrome is the most common autosomal trisomy with a prevalence of approximately 1 in 800 live births.[1] Along with other disorders such as Klinefelter's syndrome (a sex chromosome aneuploidy) and Turner's syndrome, it forms a group of chromosomal disorders called aneuploidies. By definition, aneuploidy is a condition where there is an extra or missing chromosome leading to an unbalanced chromosome number in the nucleus of the cell.[1] Aneuploidy may result in a nonviable pregnancy or offspring with congenital birth defects, failure to thrive, mild to severe intellectual disability, and a shortened lifespan. Screening tests are available for aneuploidy in all trimesters of pregnancy. The purpose of screening is to inform the parents about the possibility of chromosomal abnormalities and the options available so that they can make an informed choice.
The recommended test worldwide for screening for fetal aneuploidy at present is the “ first trimester combined test.” This test includes ultrasound and biochemical tests.[1],[2],[3],[4]
Ultrasound tests:
- Nuchal translucency [Box 1]
- Presence or absence of nasal bone.
Biochemistry:
- Free B-human chorionic gonadotropin
- Pregnancy-associated plasma protein A.
This test should ideally be offered to all pregnant women, irrespective of the maternal age. Newer tests such as noninvasive prenatal testing represent a potential option for the future[6].
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | |  |
| 1. | Committee on Practice Bulletins-Obstetrics, Committee on Genetics, and Society for Maternal-Fetal Medicine. Practice Bulletin No. 163: Screening for Fetal Aneuploidy. Obstet Gynecol 2016;127:e123-37.  |
| 2. | Driscoll DA, Gross S. Clinical practice. Prenatal screening for aneuploidy. N Engl J Med 2009;360:2556-62. |
| 3. | Nicolaides KH. Screening for fetal aneuploidies at 11 to 13 weeks. Prenat Diagn 2011;31:7-15. |
| 4. | Summers AM, Langlois S, Wyatt P, Wilson RD; Society of Obstetricians and Gynaecologists of Canada. Prenatal screening for fetal aneuploidy. J Obstet Gynaecol Can 2007;29:146-79. |
| 5. | Russo ML, Blakemore KJ. A historical and practical review of first trimester aneuploidy screening. Semin Fetal Neonatal Med 2014;19:183-7. |
| 6. | Nicolaides KH, Azar G, Byrne D, Mansur C, Marks K. Fetal nuchal translucency: Ultrasound screening for chromosomal defects in first trimester of pregnancy. BMJ 1992;304:867-9. |
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