Edwards Syndrome by sofiaie


									          Edwards Syndrome

              Kylie Allen

           Medical Genetics

R. Ostrowski, PhD. and L. McNally, M.S.

             July 6, 2002

       Edwards syndrome is a common chromosomal abnormality caused by nondisjunction.

Through karyotyping and various prenatal techniques, Edwards syndrome can be diagnosed before the

birth of a child. Many children with this disorder do not live to their first birthday; however, therapy

and other remedies can prolong the life of an Edwards syndrome child. The distinct deformities of this

abnormality include low set ears, overlapping fingers and toes, and a small head circumference, which

help distinguish it from other trisomy disorders (Disorder Zone Archives, 2001). There is no cure for

Edwards syndrome, but scientists are trying to advance their knowledge of this sporadic disease.

       Edwards syndrome was first discovered in 1960 when an extra chromosome 18 was found in

newborn babies. Edwards, et al. (along with Patau, et al., and Smith, et al.) determined that this was a

chromosomal abnormality that caused distinct malformations in babies with this disorder (Pediatric

Database, 1993).

       Edwards syndrome occurs in 1/8000 births; however, most are spontaneously aborted in the

embryonic stage. Thirty percent of the infants born with Edwards syndrome die within the first

month, 50% die within two months, and 10% survive a year. It is the second most common autosomal

aberration and second most common multiple malformation syndrome (Pediatric Database, 1993).

Phenotypic Milestones and Diagnostic Techniques

       Edwards syndrome is easily recognized by distinct dysmorphic features found in the newborn.

The typical facial phenotype of an Edwards syndrome child includes a small head circumference

(microcephaly), low-set ears, cleft lip/cleft palate, widely-spaced eyes, dropping of the upper eyelids,

an abnormally small jaw, an upturned nose, and a prominent back portion of the head (see Figure 1).

On the extremities of the body there are rocker bottom feet, underdeveloped or absent thumbs,

overlapped fingers (see Figure 2), underdeveloped nails, and webbing of the second and third toes.

Overall, these babies are severely retarded, hypertonic (rigid), and have growth deficiencies, breathing

difficulties, feeding difficulties, and developmental delays. Although Edwards syndrome babies are

mostly girls, the males that are born with this disorder have undescended testicles (Disorder Zone

Archives, 2001).

       Edwards syndrome is found by a technique called karyotyping. Karyotyping allows a

physician to view a layout of a patients’ chromosomes. In doing this, a clear picture of three
chromosomes (trisomy) in 18 is seen in Edwards babies (see Figure 3). Intrauterine studies can also

be used to determine if the baby has this abnormality. If the mother has an overly large uterus during

pregnancy, and if there is feeble fetal activity and excessive fluid in the fetal sac, the child may be at

risk of Edwards syndrome (Disorder Zone Archives, 2001).

       Not all Edwards syndrome cases are detected before birth. The first symptoms of an Edwards

baby are a low birth weight, a weak cry, and the baby is either frail or does not survive (see Figure 4;

Disorder Zone Archives, 2001).


       Although there have been numerous studies on Edwards syndrome, geneticists have not been

able to find a cure for this deadly disorder. There are, however, treatments for the individual

symptoms of Edwards syndrome. For example, many babies can undergo therapy for their breathing,

feeding, and muscle abnormalities. Also, babies that suffer from low weight gain can be taken to a

nutritionist for a special diet. Irritability, hearing and vision impairments, and constipation are just a

few more symptoms that can be handled with a variety of treatments. The only problem is that there is

not a remedy for all of the difficulties these babies have to live through.

       The prognosis of an Edwards syndrome child is not very encouraging. As already mentioned,

most die within their first year of life. With intense therapy, there have only been a few miraculous

cases of children living to their tenth birthday (Disorder Zone Archives, 2001).

       A continuous study is being done to find a cure for Edwards syndrome. Scientists have posed

questions for the further development of research techniques that may be possible in the near future.

These questions include theories on the molecular structure of Edwards syndrome and the natural

history of the affected person.
       Edwards syndrome is an abnormality that is one of the most common malformation disorders

yet seems to still boggle the minds of geneticists. There is no hereditary pattern that it follows and no

other way of tracking who is going to contract this deadly disease. Because of its sporadic nature,

Edwards syndrome has been very difficult to diagnose and impossible to cure. As technology and

knowledge increases, we can only hope that sometime in the near future there will be some sort of

permanent treatment to help those affected with Edwards syndrome.

Disorder Zone Archives. <http://www.specialchild.com/archives/dz-038.html>. 2001.

       (Date accessed July 6, 2002).

Klatt, Dr. Edward C., MD.

       <http://mirrors.cmb.ro/medgen.genetics.utah.edu/photographs.htm>. (Date accessed July 7,


Pediatric Database. <http://www.icondata.com/health/pedbase/files/TRISOMY2.HTM>.

       November 12, 1993. (Date accessed July 6, 2002).
Figure 1. This shows the facial phenotype of a typical Edwards syndrome baby with cleft lip/cleft

palate (Klatt, Dr. Edward C., MD).

Figure 2. This is an example of the overlapping of the fingers in an Edwards baby (Klatt, Dr. Edward

C., MD).
Figure 3. This Karyotyping of Edwards syndrome points out the trisomy of chromosome 18 (Klatt,

Dr. Edward C., MD).

Figure 4. This shows an Edwards syndrome newborn fighting to survive (Klatt, Dr. Edward C., MD).

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