Sex differences in neurodevelopmental trajectories in children with different levels of autistic traits.

This study tracked 824 children from birth to age 9 to see how boys and girls with autistic traits develop differently. Boys with high autistic traits had temporary language delays around age 2 but improved later. Girls with high autistic traits looked typical until after age 3, then showed declining communication skills. This suggests autism may look different in girls and boys during early development.

This longitudinal study followed 824 Japanese children from birth to 9 years, examining sex differences in developmental trajectories among children with varying levels of autistic traits. Children were classified into low, moderate, and high autistic trait groups using standardized measures. The research revealed distinct sex-specific patterns in the high autistic trait group: males showed temporary expressive language decline around age 2 with subsequent improvement, while females showed no obvious early differences but demonstrated declining communication abilities after age 3.5. These findings suggest that females and males with elevated autistic traits may exhibit different developmental phenotypes during early childhood, with implications for early identification and intervention approaches.

Findings suggest screening and assessment protocols should consider sex-specific developmental patterns. Early intervention for males might focus on language support around age 2, while monitoring of females should extend beyond age 3 to capture later-emerging communication difficulties.

Single cohort study from Japan may limit generalizability to other populations. The study used trait measures rather than clinical diagnoses, and the abstract doesn't specify statistical significance of observed differences or control for potential confounding variables.

Little is known about early manifestations of autism spectrum disorders (ASD) in females, including those who may be overlooked by the current diagnostic criteria. We longitudinally explored sex differences in the trajectories of cognitive and motor functions and adaptive behaviors in children with different levels of autistic traits. The participants were 824 children from the Hamamatsu Birth Cohort for Mothers and Children (HBC Study), Japan, who were classified into three autistic trait groups-low, moderate, and high-based on the Social Responsiveness Scale-Second Edition. Cognitive and motor functions were measured at seven time-points from 0.5 to 3.5 years of age using the Mullen Scales of Early Learning.

Adaptive behaviors were measured at five time-points from 2.7 to 9 years of age using the Vineland Adaptive Behavior Scales-Second Edition. Trajectories were depicted using latent growth curve modeling. Sex-specific trajectories were observed in the high-autistic-trait group, with only males showing a temporary decline in expressive language around the age of 2 years and a slight improvement thereafter. They also showed a slight improvement around 3 years in the adaptive behavior communication domain but a gradual downward trend later.

Females in the high-autistic-trait group showed no distinct manifestation before the age of 3 years but showed a downward trend after 3.5 years in the adaptive behavior communication domain. Females and males with higher autistic traits than their same-sex peers, independent of clinical diagnosis, may have different phenotypes in certain neurodevelopmental domains during infancy and early childhood.