Markers, Features & Characteristics

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Markers, Features and Characteristics - Written by Sandi



Characteristics

"There are several physical characteristics that are more common for babies with Down syndrome. They may include chubby cheeks, large, round eyes, larger tongue, smaller limbs and smaller body frame.

Newborns with Down syndrome look like babies who do not have Down syndrome. Babies and children with Down syndrome look like other members of their family."
- Written by Stephanie Mamayson for the Canadian Down syndrome Society


The first thing I believe people think of when they hear or give thought to Down syndrome are the features or characteristics of people who have Down syndrome.  Because of the set of the 21st chromosome, many of the features that people notice in people who have Down syndrome are present.  But it is important to understand that just because a person has Down syndrome, it doesn`t mean that they will have the same common features as all the other people who have Down syndrome.  Each person, with or with a genetic abnormality has unique attributes and features.  No two people are exactly the same in appearance (except possibly identical twins), and just as a typical child resembles their family, so does the child who has Down syndrome.  However, since Down syndrome tends to have features that are common amongst the Down syndrome community, it is acceptable to suggest that people with Down syndrome can look somewhat similar to one another.  Here is a list of common features found (but not unique to) Down syndrome.  While people who have Down syndrome seem to have features that are more commonly found in this genetic arrangement, they all do not share every single one, can have more or less then each other or even few to none at all.  So just as the general population is unique as a whole, it to can be said for those with Down syndrome to one another.

Markers, Features and Characteristics:

Some of the features that I am listing here are ones that can be seen or detected in prenatal ultrasounds.  I have included them because I am often asked for lists of items or "Markers" that are looked for by doctors and technicians when there is a concern about Down syndrome in pregnancy.  There are some "soft markers" (which are usually features or characteristics) that are actually medical issues/concerns.  The medical markers that do not really affect health are usually called minor markers also.  The more concerning medical issues which may affect health are referred to as major markers.  The term "soft marker" refers to markers which are loosely seen to be related to the genetic concern in question (Down syndrome) and can be seen in the syndrome just as often as in someone without the syndrome.  They are week markers or are nearly certain signs.  The term "hard marker" is a marker that is seen more often in that syndrome then anywhere else and those markers are considered to be more concrete, stronger markers in occurrence.  And even more specific are the categories of how all these markers are looked for, Ultrasonographic markers (sonogram/ultrasound), biochemical markers (blood work) and Invasive markers (Amniocentesis, CVS).  Either way both of these soft or hard markers seem or tend to occur at a higher frequency to people who were diagnosed with Down syndrome.  Some of these "markers" and medical issues are not always or only found in Down syndrome (though there is a higher incidence), often they occur across typically developing fetuses and babies.  But when and if these items are seen in conjunction with other "markers" or concerns, the chance of a Down syndrome diagnosis tends to be higher.  Though it should also be noted that the same can be said (a Down syndrome Diagnosis) when few or none of these "markers" or medical concerns are seen or are present.  It is equally important to note that these items (markers/characteristics) can be isolated events, which is usually more likely to suggest that there is no genetic abnormality but if one alone is alone, doctors and technicians will want to follow up more closely to watch for other concerns.

 

Here is a list of many of the more common (there may be others) markers and characteristics (some are detected during pregnancy, others after birth):

  • Low set/floppy ears (lack of cartilage)
  • Up slanting corners of eyes
  • Skin folds in the inner corners of eyes (Epicanthal folds)
  • Hypotonia (Low muscle tone/floppiness)
  • Small/flattened nose/lack of nasal bridge or bones (In 100 ultrasounds with confirmed Ds, 73% the nasal bone was missing and 27% were not)
  • Palmer crease/single palm crease/transverse crease (on hand or foot print) - called a Simian Crease
  • Sandal toe (Gap between first and second toes)
  • Shorter "long" bones (ie: Femurs or Humerus) sometimes ultrasounds will show gestation measurements to be a few weeks behind from actual.
  • Smaller sized head circumference at birth or prenatally
  • E.I.F. (Echogenic Intracardiac Focus) or simply a bright spot seen on the heart, absolutely harmless to health
  • Echogenic bowel pattern (bright spot seen on the bowels)
  • Ventriculomegaly (Larger Ventricles in head which can be mild, moderate or severe)
  • Skin folds/thick skin at the nape (back) of the neck (NT or Nuchal Translucency scan is used to see this area)
  • Higher/longer forehead
  • Shorter/pudgier fingers and toes
  • Shoter stature (average height for females is 4' 11", and males is 5' 4")
  • Clinodactyly of the 5th finger (Curved inward pinkie fingers)
  • Smaller mouth (making tongue seem larger or protruding from mouth)
  • Jagged or pointy baby teeth (and random order or different first appearing teeth)
  • Cleft pallet at birth (sometimes rare, but known to happen)
  • Lower/smaller roof of mouth
  • Sparse or thin hair (and longer lasting bald spots)
  • Brushfield Spots (white spots or flecks on the iris of the eyes)
  • Heart defects seen at birth or prenatally (Examples: Congenital Heart Disease, ASD/VSD/AVSD/PDA, valves etc.)
  • Hypospadias (Misplaced penis opening - the opening is on the underside of the head of the penis, near where it joins the shaft, but it can be anywhere along the underside of the shaft or even at the root of the penis near the testicles)
  • Fetal Pyelectasis (Enlargement/dilation of the part of the kidney that collects urine)
  • Bowel blockages/obstructions or issues
  • Choroid plexus cyst (CPC) Brain cysts - (They are likely harmless, and studies have shown that they have no effect on infant and early childhood development.)

 

I have been asked many times, which are soft or hard markers and which are serious and which are not.  Before I comment on that, it is very important for you to speak to your own family doctor or genetic doctor because, some of these markers are more common or less common in different areas, and also the seriousness of the medical concerns do differ depending on what is discovered (size, amount, placement etc.).  It is also fact that some of these markers can disappear or resolve during the pregnancy, and may not be a factor at birth or ever after.  Some of the items that can resolve (during pregnancy or after birth) are:

Ventriculogmegaly, NT measurement, Heart Defects (some), Fetal Pyelectasis, Choroid Plexus Cyst.

There are also items that should be checked or followed up on after birth (because these findings during pregnancy may resolve, it's important to ensure the actual findings (size, quantity, severity) after pregnancy and also to ensure that other's were not missed.  (My son's heart defect called an Atrial Septal Defect (ASD or hole in the heart) measuring 8mm was completely missed on all ultrasounds and fetal echo-cardiogram - an extremely high level ultrasound designed to identify heart defects).  These items include but are not limited to:

All the above last mentioned items that can resolve during pregnancy,
Heart defects,
Gastro-intestinal area (including Refulx),
Vision,
Hearing.

 

There are some specific health conditions that are more comonly associated with Down syndrome, (which are not exclusively limited to Down syndrome) but those who have Ds, tend to be more predisposed to them.  You can read those in my next article, "Health Concerns".