Every twelvemonth , doc diagnose more than 6,000 baby in the U.S. with Down syndrome , affecting 1 in 700 baby . ( 1 ) And while nearly all children born with Down syndrome share some common challenge and equipment characteristic , the term is a wide - ranging one that comes in several types and can present in dissimilar way . Here are some helpful bedrock when it comes to understand the disorderliness .
What Is Down Syndrome?
By definition , Down syndrome is a genetic shape whereby an individual has a surplus of deoxyribonucleic acid material , saysMary Pipan , MD , a behavioral baby doctor and director of the Trisomy 21 Program at Children ’s Hospital of Philadelphia .
A quick genetics deterrent example is in all likelihood in order here .
Every cellphone in a mortal ’s eubstance incorporate their genetic code , or DNA , which typically consists of 23 span of chromosomes — with one chromosome in each pair come from the child ’s female parent and the other chromosome in each yoke come from the child ’s forefather . ( 2 ) Those 46 chromosomes are a mortal ’s familial design — the material that makes them who they are , determining thing like eye coloration and inherited endangerment of dissimilar diseases .
When someone has Down syndrome , they have all 23 span of their chromosome , but they are also born with an redundant full or partial written matter of the 21st chromosome , Dr. Pipan explicate . The condition is sometimes referred to as “ chromosome 21 Down syndrome ” or “ trisomy 21 Down syndrome ” because of this third copy of the 21st chromosome .
Every chromosome carry dozens , 100 , or even yard of specific cistron . Pipan points out that many disorderliness stem from a individual gene mental defectiveness or mutation . Cystic fibrosis and muscular muscular dystrophy are two examples of these single - factor disorder .
The twenty-first chromosome has 300 cistron , and at least two of them — and potentially more — lead to Down syndrome . These genes are located in the so - called Down syndrome critical region , a chromosome 21 segment aim to contain factor responsible for many feature article of Down syndrome , including craniofacial dysmorphology .
“ So it ’s a pretty complicated upset , ” Pipan articulate .
The extra genetic material is present from the minute of conception , so Down syndrome is not something a individual can develop after birth or later in life : You ’re either born with it or you ’re not . Also , because every cell in the body has the surplus twenty-first chromosome , minor with Down syndrome “ may have medical condition that affect every part of the body , ” Pipan adds .
There Are Three Different Types of Down Syndrome
While all shape of Down syndrome are associated with an surplus full or fond copy of the 21st chromosome , there are a few unlike case of the consideration . Those type are :
Are There Varying Levels of Down Syndrome?
Every mortal with Down syndrome is unparalleled , and that uniqueness extends to the ways their shape of the condition is expressed , saysH. Craig Heller , PhD , a prof of biology and theatre director of the Center for Down Syndrome Research at Stanford University in Palo Alto , California . While many people with Down syndrome will experience similar intellectual , medical , and strong-arm challenges , those challenges can differ in severity , Heller explain .
“ Facial - cranial features , for example , are well-nigh always present , ” says Heller , look up to the distinctive coming into court ofindividuals with Down syndrome .
A drop face — especially across the nose — and upward - slanted , Amygdalus communis - shaped eyes are two of the vulgar strong-arm features of Down syndrome . Some of the other common physical characteristics include a short neck , small hands and invertebrate foot , small height , and a deficiency of muscle tone .
While some individuals with Down syndrome do not experience any other effects from the disease , Heller aver problems with digestive function , immune function , and heart office are all common . So are issues with bone denseness , free weight ascendency , and spoken communication .
Intellectual disablement are also common . “ There can be impression on learning and computer storage , and specifically the ability to take form foresighted - term memories , ” Heller say .
But he emphasizes that every individual with Down syndrome is dissimilar .
“ We surely see some kids who are less affected than others , but we shy away from terminus like ‘ low - operate ’ and ‘ high - function , ’ ” Pipan explains . Some tyke with Down syndrome have a hard time learn to walk , and others have no problem running and leap and riding a bicycle . also , some individuals with Down syndrome may sputter to learn to read while others do n’t , she says .
Pipan emphasizes that there are also electropositive characteristics associated with Down syndrome . “ Children with Down syndrome are more often than not really social and forthcoming , for example , ” she says .
“ Every someone with Down syndrome has their own enduringness and helplessness , ” she total . “ Given the correct support , they can accomplish a lot . ”
The Takeaway
Additional Sources
Joy Tanaka , Ph.D. , differentiate in clinical molecular genetics . She is dedicated to integrate first-class clinical tending with cut - boundary aesculapian research for patients with rare and undiagnosed disorders , and is focused on pursuing questions at the interface between genetic science and human disease with the goal of developing novel therapies and intervention . Dr. Tanaka received her Ph.D. from Yale University School of Medicine , where she was a Howard Hughes Medical Institute Medical Research Scholar and recipient of the George Robert Pfeiffer Fellowship for Translational Medicine . She complete her clinical fellowship in cytogenetics and clinical molecular genetic science at Columbia University and New York Presbyterian Hospital , and is presently associate clinical laboratory director at Rady Children ’s Hospital Institute for Genomic Medicine in San Diego , California .
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