Head circumference below two standard deviations below mean for a given age and gender (≤ 5th percentile).

Causes

  1. Primary:

    • Trisomies:
      • Down Syndrome (Trisomy 21)
      • Patau (13) and Edward (18) Syndromes
    • Syndromes
      • Example: Cornelia de Lange Syndrome
  2. Secondary:

    • TORCH
    • Traumatic brain Injury
    • Post natal infections
    • Alcohol (Fetal Alcohol Syndrome)