The extra genetic material from the extra eighteenth chromosome can cause a wide variety of problems (sometimes referred to as birth defects) in the developing child in the mother’s womb and after birth. Just as children with Down syndrome can range from mildly to severely affected, the same is true for children with Trisomy 18. This means that there is no hard and fast rule about what Trisomy 18 will mean for a specific child. Each child has their own unique profile of how Trisomy 18 is affecting their developing body and organs. However, all studies on survival rates show that there is a high mortality rate for children with Trisomy 18 before or shortly after birth.
Common Problems associated with Trisomy 18 can include:
- Heart defects:
- VSD (Ventricular Septal Defect): a hole between the lower chambers
- ASD (Atrial Septal Defect): a hole between the upper chambers
- Coarctation of the aorta: a narrowing of the exit vessel from the heart
- Kidney problems
- Part of the intestinal tract is outside the stomach (omphalocele)
- The esophagus doesn’t connect to the stomach (esophageal artesia)
- Excess amniotic fluid (polyhydramnios)
- Clenched hands
- Pocket of fluid on the brain (choroid plexus cysts)
- Rocker bottom feet
- Delayed growth
- Small jaw (mycrognathia)
- Small head (microcephaly)
- Low-set ears
- Strawberry-shaped head
- Severe developmental delays
- Umbilical or inguinal hernia
To read more about the general characteristics of Trisomy 18 for impacted children, you may find the following review articles helpful. You can download to read at no charge: