Mapping the causes and long-term consequences of Developmental Language Disorder

Developmental language disorder (DLD) is a common deficit in language development without any general developmental delays or neurological problems. DLD affects up to 8% of children worldwide, and language problems persist over time.

Studies from other countries have shown that DLD is associated with adverse long-term outcomes in adolescence and adulthood, such as adverse social and academic functioning, unemployment, and mental illness.

Similar to many brain-related disorders, it has been suggested that a strong genetic component is involved in the etiology of DLD, and we, among others, have shown that rare genetic factors play a role in the disorder. However, both behavioral and molecular genetics studies of DLD are still sparse.

In Swedish settings, research focusing on both long-term outcomes and understanding the etiology of the disorder is lacking.Our study proposed here aims to fill these gaps in the knowledge of causes and consequences of DLD as well as reveal the stability of language problems in individuals with DLD from childhood to adulthood in Swedish society.

For our aims, we will use three different Swedish cohorts, including a large twin sample, a unique detailed phenotype cohort of children with DLD for longitudinal investigations, and a new study sample collected within this project targeting young adults and adults with DLD.

These cohorts will be used to map the long-term outcomes of DLD, including academic performance, mental health, and living conditions.

Additionally, we will estimate the heritability of DLD, analyze its genetic correlations with neuropsychiatric disorders, and plan to conduct additional molecular genetic studies.Our results will provide knowledge of prognoses of DLD functioning and contribute to improvements of how to support individuals with DLD throughout life.