Social and Communication Development in Infants with Isolated Agenesis of the Corpus Callosum

Objective: To evaluate the development of social behavior, communication, emotion regulation, and repetitive behaviors in infants with congenital malformation of the corpus callosum, specifically those with isolated agenesis of the corpus callosum (ACC), in comparison with infants who are developing typically. Study design: This case-control longitudinal observation study examined parent report of social behavior, social-communication, emotion regulation, and repetitive behavior development in community-ascertained infants (n = 156) and infants with isolated ACC (n = 57) between 12 and 24 months of age. Results: Infants with isolated ACC produced fewer words at 12 (P =.003) 18 (P <.001), and 24 months of age (P =.003) and fewer gestures at 12 (P <.001), 18 (P <.001), and 24 months of age (P <.001). In addition, the ACC group demonstrated delays in reciprocal social behavior at 18 months (P =.01) and social competence at 12 (P <.001) and 18 months (P =.01). No concerns were noted in emotion regulation or restricted and repetitive behavior, and social behavior appeared to normalize at 24 months. Conclusions: Existing data suggest heterogeneity in developmental outcomes among individuals with isolated ACC. The current findings fill a gap in knowledge about development in the second year of life. Surveillance of social and communication ability in infants with ACC may be warranted. The role of the corpus callosum in facilitating rapid interhemispheric information processing affects skills beyond the motor system. More work is needed to identify intervention targets for infants and toddlers with ACC.