Edwards Syndrome (Trisomy 18)

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Description

Edwards syndrome, also known as trisomy 18, is a rare genetic condition that occurs when a person has an extra copy of chromosome 18. This extra genetic material disrupts normal development, leading to a range of physical and intellectual challenges. While there is no cure, early intervention and support can significantly improve quality of life for individuals with Edwards syndrome and their families.

Genes Involved

Edwards syndrome is caused by an extra copy of chromosome 18. The exact genes on chromosome 18 that contribute to the condition are not fully understood, but it is believed that the extra genetic material disrupts normal development, leading to the observed characteristics.

Recognizing the Signs and Symptoms

Individuals with Edwards syndrome exhibit a wide range of physical and developmental characteristics, including:

• Physical Features:
  • Small size at birth (low birth weight)
  • Small head (microcephaly)
  • Prominent occiput (back of the head)
  • Clenched fists with overlapping fingers
  • Small jaw (micrognathia)
  • Low-set ears
  • Heart defects (e.g., ventricular septal defect, patent ductus arteriosus)
  • Kidney problems
  • Cleft lip or palate
  • Clubfoot
  • Short, webbed neck
  • Rocker-bottom feet
• Developmental Delays:
  • Intellectual disability
  • Delayed motor skills (e.g., sitting, walking)
  • Feeding difficulties
  • Seizures
  • Respiratory problems

Causes

Edwards syndrome occurs due to a random error during cell division called non-disjunction. This error can happen during the formation of either the egg or sperm cell, resulting in an embryo with three copies of chromosome 18 instead of the usual two.

Inheritance/recurrence risk

Edwards syndrome is not usually inherited. The majority of cases occur due to a random error during cell division. However, there is a small chance of the condition recurring in future pregnancies. The risk of recurrence depends on several factors, including the age of the parents and the specific cause of the syndrome. Genetic counseling can help assess the risk of recurrence in future pregnancies.