Etiology
Congenital/Intrinsic
- Familial (autosomal dominant, autosomal recessive)
- Syndromes (trisomy 21/13/18)
- Craniosynostosis
- Small brain (neuronal migration defects, CP, anencephaly)
Acquired
- Infection (TORCH, meningitis)
- Maternal drugs (FASD, tobacco, illicit substances)
- IUGR (symmetric – genetic, congenital anomalies, intrauterine infections, substance abuse, cigarette smoking and therapeutic irradiation)
- CVA
- Metabolic (maternal PKU)