Exploring the Contribution to ADHD of Genes Involved in Mendelian Disorders Presenting with Hyperactivity and/or Inattention

• Published in: Genes 2021-12, Vol.13 (1), p.93
• Main Authors: Fernàndez-Castillo, Noèlia, Cabana-Domínguez, Judit, Kappel, Djenifer B, Torrico, Bàrbara, Weber, Heike, Lesch, Klaus-Peter, Lao, Oscar, Reif, Andreas, Cormand, Bru
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adults; Aged; Aggressiveness; Attention Deficit Disorder with Hyperactivity - epidemiology; Attention Deficit Disorder with Hyperactivity - genetics; Attention Deficit Disorder with Hyperactivity - pathology; Attention deficit hyperactivity disorder; Autism; Case-Control Studies; Comorbidity; Female; Foxp1 protein; Gene expression; Genetic disorders; Genetic Markers; Genomes; Genomics; Health risk assessment; Heredity; Humans; Hyperactivity; Impulsive behavior; Impulsivity; Male; Middle Aged; Neurodevelopmental disorders; Obsessive compulsive disorder; Personality traits; Phenotype; Pneumonia, Aspiration - genetics; Pneumonia, Aspiration - pathology; Whole Exome Sequencing; Young Adult
• ISSN: 2073-4425; 2073-4425
• DOI: 10.3390/genes13010093

Attention-deficit hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder characterized by hyperactivity, impulsivity, and/or inattention, which are symptoms also observed in many rare genetic disorders. We searched for genes involved in Mendelian disorders presenting with ADHD symptoms in the Online Mendelian Inheritance in Man (OMIM) database, to curate a list of new candidate risk genes for ADHD. We explored the enrichment of functions and pathways in this gene list, and tested whether rare or common variants in these genes are associated with ADHD or with its comorbidities. We identified 139 genes, causal for 137 rare disorders, mainly related to neurodevelopmental and brain function. Most of these Mendelian disorders also present with other psychiatric traits that are often comorbid with ADHD. Using whole exome sequencing (WES) data from 668 ADHD cases, we found rare variants associated with the dimension of the severity of inattention symptoms in three genes: , , and . Then, we focused on common variants and identified six genes associated with ADHD (in 19,099 cases and 34,194 controls): , , , , , and . Furthermore, , , and were nominally associated with autism spectrum disorder (ASD) (18,382 cases and 27,969 controls), as well as with anxiety (7016 cases and 14,475 controls), and with aggression (18,988 individuals), which is in line with the symptomatology of the rare disorders they are responsible for. In conclusion, inspecting Mendelian disorders and the genes responsible for them constitutes a valuable approach for identifying new risk genes and the mechanisms of complex disorders.