Postnatal-Onset Microcephaly: Pathogenesis, Patterns of Growth, and Prediction of Outcome

Abstract

OBJECTIVE: Although children with postnatal-onset microcephaly (POM) generally have poor development, we speculated that better somatic growth would predict better development in these children. PATIENTS AND METHODS: We followed 57 children with POM for an average of 4.2 years (13 encephaloclastic, 14 dysgenetic, 6 with Rett syndrome, 24 idiopathic) and calculated the developmental quotient (DQ) at each visit (DQ > 0.70 was considered normal). SD scores (SDS) for measurements were analyzed using a repeated measures mixed-effects model to assess effect of weight, height, head circumference (HC), and age on DQ. Pearson's correlation was used to examine the independent influence of each variable on final DQ. RESULTS: Forty-four children (77%) had a low DQ (mean: 0.33), but 13 (23%) had a normal DQ (mean: 0.93), including 10 idiopathic and 3 encephaloclastic. Mean HC fell below −2 SDS in all before 1 year (destructive at 3.3 months, idiopathic low-DQ at 7.5 months, dysgenetic at 8.5 months, Rett syndrome at 11 months, and idiopathic normal-DQ at 11.5 months). Mean weights and heights both fell below −2 SDS for all low-DQ groups but remained normal in both normal-DQ groups. Weight, height, and HC were independent predictors of DQ (P < .0001). Final DQ correlated with weight (r = 0.27), height (r = 0.41), and HC (r = 0.13). CONCLUSIONS: Most children with POM have poor later development. Whatever the cause of POM, persons in whom postnatal body growth (weight, height, HC) is better sustained have more favorable development, and in one-quarter of such persons (mostly idiopathic POM), final DQ is normal.