Academic underachievement refers to school performance which falls below expectations. Focusing on the pivotal first stage of education, we explored a quantitative measure of underachievement using genomically predicted achievement delta (GPA[delta]), which reflects the difference between observed and expected achievement predicted by genome-wide…

This study investigated the systematic rise in cognitive ability scores over generations, known as the "Flynn Effect," across middle childhood and early adolescence (7-15 years; 291 monozygotic pairs, 298 dizygotic pairs; 89% White). Leveraging the unique structure of the Louisville Twin Study (longitudinal data collected continuously…

Background: Sensory processing differences are reported both in children with ADHD and in children with autism. Given the substantial overlap between autism and ADHD, the current study examined which sensory features were uniquely predictive of autistic traits after controlling for ADHD symptoms, age, IQ, and sex in a sample of children and…

Despite the importance of self-control for well-being and adjustment, its development from early childhood to early adolescence has been relatively understudied. We addressed the development of mother-reported self-control in what is likely the largest and longest longitudinal twin study of the topic to this day (N = 1889 individual children with…

Children with Coloboma, Heart defects, Atresia choanae, Restricted growth, Genital hypoplasia, and Ear abnormalities (CHARGE) syndrome have many sensory impairments that can cause delays in motor development impacting physical activity, health, and quality of life. However, only one limited study has investigated motor competence in children with…

The study aimed to identify the mediating role of emotional intelligence and social competences in the relationship between gender and broad autism phenotype (BAP) as well as between age and BAP. It comprised 85 parents of children with ASD. They completed the questionnaires of Autism-Spectrum Quotient, social competences, and emotional…

Feeling inhibited and socially not at ease is reflected in the trait social inhibition (SI). SI is associated with psychopathology that arises in young adulthood, such as anxiety. We aim for a better insight into the genetic and environmental contributions to SI across the life span, and as such examine their contributions to SI stability and…

Clinical genetic testing is recommended for individuals diagnosed with autism spectrum disorder. There are only a few reports of how these recommendations are followed and especially missing for European countries. We aimed to analyze the rate of access, utilization, and awareness of clinical genetic testing among autistic individuals in Sweden…

To date, health related quality of life (QoL) has not been systematically evaluated in youth with fragile X syndrome (FXS), the most common single gene cause of autism and the most common inherited form of developmental disability. We describe QoL data gathered using the Pediatric Quality of Life Inventory (PedsQL) completed online by 364 parents…

Sleep is important for child development. Sleep problems in early childhood are associated with negative outcomes across numerous domains, including executive control, internalizing and externalizing psychopathology, and social competence (Astill et al., 2012; Hysing et al., 2016; Spruyt et al., 2019). Little research has focused on moderators…

Early diagnosis of autism spectrum disorder is challenging due to its phenotypic and etiological heterogeneity, but critical for implementation of early interventions. We examined the age of autism spectrum disorder diagnosis in a sample of 554 children and adolescents enrolled in the ELENA cohort study in France with regard to the influences of…

Objectives: This paper explores the relationship between speech therapy intensity and parent satisfaction with speech therapy (ST) in children with Phelan-McDermid Syndrome (P-MS), a rare genetic disorder. Methods: ST intensity ("ST Dose [minutes per session]") × ("ST Dose Frequency") × ("ST Length [years]") and…

Gold-standard diagnostic assessments of autism spectrum disorder (ASD) symptomatology were conducted on 63 children (mean CA: 8.81 years) with 7q11.23 duplication syndrome, one of the copy number variants identified by Sanders et al. ("Neuron" 70:863-885, 2011a) as associated with ASD. ASD classification rate was 39.6% for the Autism…

It is well documented that mothers of children with challenging behavior (CB) experience elevated levels of stress and that this persists over time, but less is known about the experience of mothers of children with rare genetic syndromes. This article describes 2 studies, 1 cross-sectional and 1 longitudinal, comparing well-being in mothers of…

Purpose: This review article summarizes a program of longitudinal investigation of twins' language acquisition with a focus on causal pathways for specific language impairment (SLI) and nonspecific language impairment in children at 4 and 6 years with known history at 2 years. Method: The context of the overview is established by legacy scientific…