However, many people who have Down syndrome usually do not develop all of the characteristics.
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How Common Is Down Syndrome?
No therapy can prevent the effects of the extra chromosome if a child has it.
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This may affect outcomes.
In a small reasearch small study, Hispanic/Latino boys with Down syndrome were more likely to have obesity.
The incidence is approximately the same for babies of any sex.
Illustration by Laura Porter for Verywell Health
The developmental effects of Down syndrome begin in utero (before an affected baby is born).
Down syndrome takes place if a developing baby inherits three copies of chromosome 21 instead of two copies.
The extra chromosome can come from either parent.
Risk factors include:
What Are the Mortality Rates for Down Syndrome?
Screening for Down syndrome includes testing during the pregnancy.
However, not all babies with Down syndrome have developmental organ abnormalities.
Quad Test
The quad testis a blood test that can be done after 15 weeks of pregnancy.
Amniocentesis
Amniocentesistakes a sample of theamniotic fluid(the fluid surrounding the fetus) for chromosomal analysis.
It is the most definitive diagnostic test for Down syndrome during pregnancy.
It can be done after the 15th week of pregnancy.
This procedure has a very low risk of complications.
Recommendations
Screening is recommended for pregnant people who are 35 years of age or older.
It is also recommended for pregnant people younger than age 35 who have had a child with Down syndrome.
Pregnant people who are at risk are not obligated to have screening for Down syndrome.
Those who are at low risk can often request the screening tests.
Summary
Down syndrome is a lifelong condition that occurs due to an extra copy of chromosome 21.
It is a lifelong condition that can cause disabilities.
Often, medical and practical interventions can alleviate some of the effects and improve quality of life.
Down syndrome occurs due to a parental chromosomal abnormality, but it affects the child and not the parents.
Down syndrome can be diagnosed during early pregnancy with an amniocentesis chromosome test.
Amniocentesis is a procedure in which a sample of fluid is taken from a pregnant person.
The punch in of malformations each person has may differ.
2021;57(7):651. doi:10.3390/medicina57070651
Stanford Children’s Health.Down syndrome (trisomy 21) in children.
