Down Syndrome Overview (cont.)

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What are the signs and symptoms of Down syndrome?

The baby with Down syndrome has a hallmark appearance. However, every aspect of the appearance does not need to be present as the phenotype, the way the genes make the child look, can be markedly different for each patient.

Commonly, there is a small head and short neck, a flat face, and upward slanting eyes. Ears are flat and positioned lower than “normal.” The tongue protrudes and seems to be too large for the mouth. Hands tend to be wide, with short fingers and there is just a single flexion crease in the palm. Joints tend to be more flexible and muscles may lack tone.

The patient may have growth retardation and though as a baby may be normal size, will not grow as tall. Average height for an adult male with Down syndrome is 5 ft 1 in and for a female it is 4 ft 9 in. Bowleggedness is common. Obesity occurs with aging.

There is decreased mental function and the IQ may range from mild disability (50 to 70) to moderate (35 to 50). For patients with Mosaic Down Syndrome, the IQ can be 10 to 30 points higher. There can be language development delay both from hearing impairment and speech delay. Gross motor skills like crawling and walking can be slow to mature and fine motor skills may take time to develop.

How is Down syndrome diagnosed?

Most often, Down syndrome is diagnosed while the fetus is still in the uterus (see tests below). Routine screening is recommended by the American College of Obstetrics and Gynecology in all pregnancies, regardless of the mother's age.

In the first and second trimesters of pregnancy, blood tests and ultrasound may be used to screen for not only Down syndrome, but also spina bifida and other genetic abnormalities. Should these screening tests show the potential for Down syndrome, specific diagnostic test may be considered. These include the following:

  • Amniocentesis: A needle is placed using ultrasound guidance into the uterus to obtain a sample of the amniotic fluid that surrounds the fetus. The fetus' chromosomes can be analyzed, looking for trisomy 21.
  • Chorionic villus sampling: Cells are taken from the placenta for fetal chromosome analysis.

There is a small risk of miscarriage with these tests. The decision as to which test might be best and when it should be done depends upon the situation and is made jointly with mother and the health care professional.

At birth, Down syndrome is usually diagnosed by the appearance of the newborn and the health care professional will likely order a chromosome analysis to confirm the diagnosis.

Medically Reviewed by a Doctor on 6/11/2015

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