Trisomy 18

Karyotype Trisomy 18 male

Organ Malformations

1. Central Nervous System

• severe mental retardation
• hypotonia -> hypertonia
• neural tube defects
• poor suck and weak cry
• failure to thrive
• ocular anomalies

2. Respiratory

• apnea

3. Cardiovascular( >95%)

• major: VSD, ASD, PDA
• minor: transposition, ToF, coarctation, anomalous coronary artery, dextrocardia, aberrant subclavian artery, arteriosclerosis, PS, bicuspid aortic and/or pulmonic valves

4. Gastrointestinal

• inguinal, umbilical, and/or diaphragmatic hernia
• congenital defects: diastasis recti, heterotopic pancreas, malrotation, Meckel's, tracheoesophageal fistula

5. Genitourinary

• cryptorchidism
• congenital defects: double ureter, ectopic kidney, horseshoe kidney, hydronephrosis, polycystic kidney

Investigations

Imaging Studies

• to rule out organ malformations:
• cardiovascular anomalies - Echo
• gastrointestinal anomalies - Barium Swallow, Endoscope
• genitourinary anomalies - Ultrasound

Management

Supportive, very poor prognosis.

• 30% dying by 1 month of age
• 50% dying by 2 months of age
• 90% dying by 12 months of age

Genetic counselling, recurrence rate depends on genotype.

(modified from original 1999 Pedbase entry)