Edwards syndrome is a genetic disorder caused by the presence of all or part of an extra 18th chromosome. It is the second most common autosomal trisomy after Down syndrome. The majority of fetuses with Edwards syndrome die before birth and those that survive often have heart abnormalities, kidney malformations, and other organ disorders. Prenatal testing like amniocentesis or chorionic villus sampling is used to diagnose Edwards syndrome by analyzing fetal chromosomal material to detect the additional copy of chromosome 18.
1. Edwards Syndrome
Is a genetic disorder caused
by the presence of all or part
of an extra 18th chromosome.
It is the second most
common autosomal trisomy,
after Down syndrome, that
Chromosome 18 carries to term.
2. Elliott Greenfield suffering from Edwards syndrome
Edwards syndrome occurs in around one in
6,000 live births and around 80 percent of those
affected are female.
The majority of fetuses with the syndrome die
before birth
The syndrome has a very low rate of survival,
resulting from heart abnormalities, kidney
malformations, and other internal organ
disorders.
3. Signs and Symptoms
kidney malformations
structural heart defects at birth
(i.e., ventricular septal defect, atrial septal
defect, patent ductus arteriosus)
intestines protruding outside the body
(omphalocele)
esophageal atresia
mental retardation,
4. developmental delays
growth deficiency
feeding difficulties
breathing difficulties
and arthrogryposis (a muscle disorder that
causes multiple joint contractures at birth)
5. Characteristics
small head (microcephaly) accompanied by a
prominent back portion of the head (occiput)
low-set, malformed ears
abnormally small jaw (micrognathia)
cleft lip/cleft palate
upturned nose
narrow eyelid folds (palpebral fissures)
widely spaced eyes (ocular hypertelorism)
6. drooping of the upper eyelids (ptosis)
a short breast bone
clenched hands
choroid plexus cysts
underdeveloped thumbs and or nails
absent radius, webbing of the second and third toes
clubfoot or Rocker bottom feet; and in males
undescended testicles
7.
8. Diagnostic Test
Prenatal testing
Triple screen-measurement of alpha
fetoprotein (AFP) levels . It creens the
mother's blood for AFP, hCG (human
chorionic gonadotropin, the so-called
“pregnancy hormone”), and estriol (a type of
estrogen). The test is performed between the
15th and 17th week of pregnancy.
9. Ultrasound is another commonly used
screening test
Amniocentesis or chorionic villus sampling-
Analysis of fetal chromosomal material
obtained in this test is necessary to prove
that the additional copy of chromosome 18 is
present. Performed at 15-18 weeks
of pregnancy and is the most commonly used
test for the prenatal diagnosis of trisomy 18.
During the procedure a thin needle is inserted
through the abdominal wall and a small
sample of amniotic fluid is taken.
10. Chorionic villus sampling is another type of test that
allows the examination of fetal genetic material. It is
performed earlier in pregnancy (at 10-12 weeks after
the last menstrual period) and therefore carries the
advantage of allowing for an earlier diagnosis. This
procedure involves the collection a chorionic villus
cell sample from the placenta either through the
insertion of a needle in the abdominal wall or
through a catheter in the vagina.