ACQUIRED MICROCEPHALY: PATTERNS, CAUSES AND EFFECTS
Aim: To study the patterns, causes and effects of acquired microcephaly.
Methods: Acquired microcephaly was defined as a decrease in head circumference z- score (=1SD) of >1 from an initial value above –2.3, using Child Growth Foundation norms. We studied growth patterns, causes, motor (Touwen) and psychometric outcomes (IQ/DQ: BSID-II/WPPSI-R/WISC-III); literacy, numeracy, specific abilities and behaviour: WORD; WOND; NEPSY; CBCL).
Statistical analysis used odds ratios and group comparison of means.
Results: 55 children (26 boys) had median z-scores initially 0.95 (range -2.2, 1.4) which decreased by 2.6 (-2.9,-6.6); includes later recovery). Three patterns occurred: A: decreased, then grew parallel (34); B: continued decrease (14); C: later recovery (4). 3 were too young to classify. 10 had associated poor weight gain and 8 global growth delay. Causes were Idiopathic (11); Familial (1o relative >–2SD) (15)
Syndromic: (10); Symptomatic (post insult): 11). Most syndromic causes were non-specific. Most idiopathic cases had pattern A; familial and syndromic cases could have any pattern. Pattern B showed the most severe decreases in z-score. There was no significant correlation between DQ/IQ and final z scores causes or patterns.
Conclusion: Most cases did not have a specific diagnosable cause, but appeared genetic in origin. Patterns and causes are not strongly linked to each other or to outcome.
Keywords: acquired, progressive, microcephaly