Fetal abnormalities » Brain
- 1 in 6,000 births.
- Multiple echogenic nodules in the heart (rabdomyoma, usually >20 weeks’ gestation) and brain (cortical tubers and subependymal nodules, usually >30 weeks’ gestation).
- Differential diagnosis: cardiac fibroma, which are single, large and often associated with pericardial effusion.
- Tuberous sclerosis is found in 50% of cases of rabdomyoma (in the other 50% of cases the cardiac tumor is an isolated finding). When there are multiple rabdomyomas the risk of tuberous sclerosis is >90%.
- Mutations in either the TSC1 or TSC2 gene, are found in 90% of cases.
- The tumors most often affect the brain, heart, skin, kidneys, eyes and lungs. However, prenatal diagnosis is confined to detection of the lesions in the heart and brain.
- Detailed ultrasound examination, including neurosonography.
- Search for the mutations in the TSC1 and TSC2 genes.
- Fetal brain MRI may be useful if other brain abnormalities are suspected.
- Ultrasound scans every 4 weeks to monitor the evolution of cardiac tumors and development of arrhythmias and hydrops.
- Place: hospital with neonatal intensive care.
- Time: 38 weeks, but ealier if there are arrhythmias or hydrops.
- Method: cesarean section if there is hydrops.
- Arrhythmias, hydrops, and stillbirth in about 20% of cases.
- The cardiac tumors usually regress in early life, whereas the brain tumors usually increase in size and number.
- Prognosis depends on the number, size and location of the tumors.
- Wide spectrum ranging from normal life expectancy with mild symptoms to severe neurodevelopmental delay, epilepsy, autism and renal or pulmonary failure.
- Autosomal dominant: 50% if one of the parents is affected.
- De novo mutations (65% of cases): no increased risk.