Background: Parent-child interactions (PCI) in infants with an elevated likelihood (EL) of autism start to diverge from other infants toward the end of the first year. This divergence is often attributed to emerging features of autism impacting infant social interactions in ways that become increasingly amplified. The aim was to identify which, if any, 12-month autism features were associated with later PCI qualities. Method: Twelve-month-old infants (N = 103) with early autism features (3+ on the Social Attention and Communication Surveillance-Revised tool) were assessed on the Autism Observation Scale for Infants (AOSI) at 12 and 18 months, and on free play PCI using the Manchester Assessment of Caregiver-Infant Interaction at 18 months. Results: AOSI autism features at 12-months were associated with 18-month PCI qualities, independent of 18-month autism features. Specifically, infants with emerging features in social attention areas later showed less attentiveness to parents and lower dyadic mutuality. By contrast, infants with emerging sensorimotor atypicality/delay later showed increased attentiveness to parents and lower negative affect, their parents were more sensitively responsive, and their interactions were more mutual. Emotional regulation scores had no significant association with later PCI. Conclusions: The findings support the notion that PCI changes in EL infants are rooted in the transactional impact of early emerging autism-related features, which may have differential effects on PCI. Pending replication in a larger sample using a detailed measure of early autism features, the findings suggest that early autism features may amplify or elicit interactions.