trisomy 21


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Related to trisomy 21: trisomy 21 syndrome

trisomy 21

trisomy 21

Down syndrome, mongolism Pediatrics A chromosomal dysgenesis caused by partial or complete duplication of all or part of chromosome 21 appears 3 times; in some only some cells contain the chromosomal defect–ie, mosaicism Clinical MR, microcephaly, short stature, a characteristic facial dysmorphia–flat hypoplastic facies, short/flat nose, upward slanting eyes–Mongolian slant; inner corner of the eyes often has a rounded fold of skin–epicanthal fold; small, low-set ears, thickened, protruding and fissured tongue, joint laxity, pelvic dysplasia, broad hands and feet with shortened digits, a single transverse palmar or simian crease, lenticular opacification, cardiac defects–eg, PDA, endocardial cushion defects, Fallot's tetralogy, esophageal atresia, duodenal atresia, muscle spasms, ↑ risk of ALL, retardation of growth and development is typical; most never reach average adult height Risk of DS ↑ with maternal age–0.7/1000 births ≤ age 30; 34.6/1000 ≥ age 45 Prognosis Compatible with long-term survival Incidence 1:900. See Maternal age.

Patient discussion about trisomy 21

Q. Can Down syndrome occur again? A few years ago, at the age of 32 my sister gave birth to a child that was diagnosed with Down syndrome. Now, at the age of 37 she's pregnant again. Can she have another baby with Down? Does the fact she has a baby with Down means she has higher risk for a second baby with Down?

A. - Older women especially after 35 years
- Previuosly child with Down Syndrome

Video link
http://www.thedoctorsvideos.com/video/585/Downs-Syndrome

DrMFK

Q. assessment of down syndrom

A. down syndrome is a very easy diagnosis - it just need a chromosome check and seeing 3 (instead 2) chromosomes number 21. -

http://learn.genetics.utah.edu/content/disorders/whataregd/down/

Q. what does enlarged heart mean? is it linked to down syndrome? My wife is 16 weeks pregnant. we did a prenatal US and we were told that the baby hes an enlarged heart and that we are advised to do amniocentesis. A friend of mine had a baby with down syndrome, and he was toled that if they have done this procedure, the doctors could have find it on time and abort the pregnancy. Is there a clear connection between the enlarged hart and the fact that the doctor advised us to do this procedure to down syndrome?

A. Down syndrome is associated with several kinds of heart problems. those problems can cause an enlarged heart but usually it will appears as a post-natal complication.
The protocol that most obstetrics use is that if there is anything abnormal in the US there is an automatic referral to an amniocentesis procedure.
the US has a lot of false alarms, so they must check with the more accurate procedure.

More discussions about trisomy 21
References in periodicals archive ?
In our study trisomy 21 and deletion 5q were the commonest cytogenetic abnormalities found.
We computed theoretical z scores based on a given CV value, probe number, and fetal fraction using the following formula: [mean copy number (test)--mean copy number (normal)]/SD of the normal sample, where the mean copy number of the test sample containing trisomy 21 fetal DNA is 2 + fetal fraction.
The study sample had either an intermediate or a high background risk for trisomy 21, largely based on maternal age.
Trisomy 21 was seen in 17(38.64%) of the total cases observed out of which 3,4,2,1,2,1,1 cases were seen in less than or equal to 1, 2-3, 4-5, 6-7, 8-9, 10-11, 12-13 years of age respectively and no patient was seen in age group of 14-15 years, Nance-Horan syndrome was observed in 12(27.27%) cases out of which 2,1,3,2,1,1 cases were seen in less than or equal to1, 2-3, 4-5, 6-7, 8-9 and12-13 years of age respectively, while no case was enrolled in age groups 10-11 and 14-15 years.
The incidence of trisomy 21 conceptions increases with maternal age.[sup][5] Subsequently, maternal parity was established as an additional independent risk factor [sup][6] and genetic predisposition as third independent risk factor.[sup][7],[8] An increase risk for DS may be the result of an autosomal recessive gene mutation, particularly in the Middle East where the rate of consanguinity is increasing.[sup][9]
Although the detection rate of cfDNA for trisomy 21 is higher than that of traditional screening, the detection rate of traditional screening is also quite high at lower cost.
The NPV of cfDNA in this study was 100% (95% confidence interval, 99.8%-100%) for both trisomy 21 and trisomy 18.
In a study of about 1,900 low-risk women whose mean maternal age was 30 years, cfDNA testing detected all cases of trisomy 21. The PPV for trisomy 21 was 45.5% compared with 4.2% with standard screening (N.
After cell-free DNA analysis became clinically available in 2011, ACOG and SMFM recommended it for women at increased risk of fetal aneuploidy, including women 35 years or older, fetuses with ultrasonographic findings indicative of an increased risk of aneuploidy, women with a history of trisomy-affected offspring, a parent carrying a balanced robertsonian translocation with an increased risk of trisomy 13 or trisomy 21, and women with positive first-trimester or second-trimester screening test results.
Down Syndrome Research's mission is to find ways to improve the lives of people born with trisomy 21, the cause of Down syndrome.