Sex-Specific Behavioral Features of Juvenile and Adult Haploinsufficient Scn2a+/- Female Mice, Model of Autism Spectrum Disorder.

Genetic variants of the SCN2A gene, encoding the NaV1.2 sodium channel, cause a spectrum of neurodevelopmental and epileptic disorders, and are among those that show the strongest association with Autism Spectrum Disorder (ASD). ASD has a male-bias prevalence, but several studies have proposed that female prevalence may be underestimated due to different symptomatic expression compared with males. However, it is unclear whether this is related to actual different pathological features or to greater masking abilities in females. Studies on Scn2a+/- mice, a model of SCN2A haploinsufficiency and ASD, have shown an age-dependent ASD-like phenotype attenuated at adulthood in males. However, little is known about the behavioral features of Scn2a+/- female mice. We performed a battery of behavioral tests that are relevant for assessing ASD-like features, investigating juvenile and adult Scn2a+/- female mice. Our results demonstrate that female Scn2a+/- mice exhibit an overall milder phenotype than males, showing increased risk-taking in juveniles, hyper-reactivity to cold stimuli, and mild memory impairments in adults, abnormally increased sociability, and altered decision-making related behaviors in both juveniles and adults. Thus, this aligns with the male-biased prevalence of ASD and supports the existence of sex-specific phenotypic differences, potentially arising from distinct underlying pathophysiological mechanisms. Both sexes should be investigated in studies of mouse models of ASD.