Down Syndrome Was Not Discovered By Dr.
Down
Down syndrome (DS) is a condition due to a
chromosome abnormality. The chromosome abnormality leads to
impairment of
both the physical and intellectual development of the
individual.
In 1959, the late French physician Jerome
Lejeune and coworkers reported finding an extra chromosome in each of
nine children with DS. The extra chromosome in all of the children
seemed to be the same-an extra copy of chromosome number 21 . Since
having three instead of the normal two chromosomes of a specific type
is referred to as trisomy, these children had trisomy 21, now
recognized as the cause of DS.
A DS baby has certain characteristic
features that may individually be quite subtle but together permit
the clinical diagnosis of DS to be made at birth.
These signs of DS include:
- Slight flattening of the face
- Minimal squaring off of the top of the
ear
- Low bridge of the nose (lower than usual)
- A fold of skin over the inner corner of
the eye
- A ring of tiny harmless white spots
around the
iris
- Short, incurved fifth finger
- A single transverse crease across the
palm
- Increased space between the first and
second toes
There are many, many more minor
malformations in DS.
DS is associated with major malformations,
too. For
example, approximately half of DS children are born with a
heart defect,
most often a hole between the two sides of the heart.
Hirschprung's
disease (congenital aganglionic megacolon) which can cause
intestinal
obstruction occurs more frequently in DS.
DS also carries an increased risk of acute
leukemia.
This risk is small in absolute terms but is still a significant
added
risk. The intellectual handicaps in DS are of great
importance.
These handicaps may not be immediately
evident, but
they become increasingly apparent during infancy and early
childhood as
developmental delay and later in childhood and adulthood as
mental
retardation.
Very few adults with Down
syndrome can lead independent lives because of their mental
retardation. It was once thought that nearly all adults with Down
syndrome
developed Alzheimer's disease (dementia) so that on top of their
mental handicap most people with Down syndrome were slated for
premature senility. However, it now appears that a much lower
proportion, perhaps 20 to 25%, of Down's adults develop dementia. The
majority of adults with Down syndrome may thus be spared this fate.
Confirmation of the trisomy 21 requires a
chromosome
test which also serves to rule in or out a translocation (a
rearrangement)
of chromosome 21 that may be heritable and give rise to more
cases of DS
in the family.
Evaluation of the DS baby and the family by
a
medical geneticist may be useful.
Down syndrome is named after the 19th
century
English physician J. Langdon Down who described the condition
in 1866. As
a matter of fact, Langdon Down was not the first person to
describe the
condition. It was clearly recognized 20 years earlier by the
French
physician E. Seguin who descibed the condition in a book
he
published in 1846 in Paris. Such historical inaccuracies in
naming
diseases are common. However, there are stronger grounds for
not calling
this condition after Langdon Down.
In great error, Langdon Down attributed the
condition to a "reversion" to the "mongoloid
race." He
held that evolution had been reversed and there had been a sort
of
backslide from the superior Caucasian to the inferior Oriental
race.
Hence, the name Down syndrome smacks of racism.
The disorder was also once called
mongolism, a term now considered perjorative, and to be avoided in
English. (It is still used in some countries). Other names that have
been used over the years include mongol, mongoloid, mongolian
imbecile, mongoloid idiot, mongoloid deformity, Kalmuck idiocy,
Tartar, unfinished child, Langdon-Down syndrome, Down's anomaly, and
Down's deformity.
All of these names should, in our view, be
jettisoned. The least controversial and most appropriate name
for this
syndrome may simply be what causes it: TRISOMY 21.
You can learn these facts and more in
MedicineNet's Medical Dictionary!
Last Editorial Review: 4/26/2002
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