Edwards’s syndrome, also known as trisomy 18, is a genetic disorder caused by a third copy of all or part of chromosome 18. Many parts of the body are affected. Babies are often born small and have heart defects. Other features include a small head, small jaw, clenched fists with overlapping fingers, and severe intellectual disability. Children born with Edwards syndrome may have some or all of these characteristics: 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, intellectual disability, developmental delays, growth deficiency, feeding difficulties, breathing difficulties, and arthrogryposis (a muscle disorder that causes multiple joint contractures at birth). The additional chromosome usually occurs before conception. The effects of the extra copy vary greatly, depending on the extent of the extra copy, genetic history, and chance. Edwards’s syndrome occurs in all human populations but is more prevalent in female offspring.
SIGNS AND SYMPTOMS
- Slow growth before birth and a low birth weight
- A small head (“microcephaly”)
- A severe learning disability
- A small jaw (“micrognathia”)
- Malformations of the heart
- Malformations of the kidneys
- Clenched fists and overlapping fingers
- Malformed feet
- Problems with feeding and breathing
- A cleft lip (an opening between the mouth and nose, where the lip looks “split”) and/or cleft palate (an opening in the roof of the mouth)
DIAGNOSIS
A diagnosis of Edwards’ syndrome may be suspected in pregnancy during an ultrasound scan but the only way to reach a definite diagnosis is to look at the baby’s chromosomes. There are two tests that can be done during pregnancy which look at the baby’s chromosomes: Chorionic Villus Sampling (CVS) or Amniocentesis. A Genetic Counselor or Genetics Doctor can discuss these tests in the genetics clinic. Edwards’ syndrome is suspected at birth then a blood sample can be taken to look at the baby’s chromosomes.
