Attention deficit/hyperactivity disorder (ADHD) is a common and heritable phenotype frequently accompanied by insomnia, anxiety, and depression. Here, using a reverse phenotyping approach, we report heterozygous coding variations in the core circadian clock gene cryptochrome 1 in 15 unrelated multigenerational families with combined ADHD and insomnia. The variants led to functional alterations in the circadian molecular rhythms, providing a mechanistic link to the behavioral symptoms. One variant, CRY1Δ11 c.1657+3A>C, is present in approximately 1% of Europeans, therefore standing out as a diagnostic and therapeutic marker. We showed by exome sequencing in an independent cohort of patients with combined ADHD and insomnia that 8 of 62 patients and 0 of 369 controls carried CRY1Δ11. Also, we identified a variant, CRY1Δ6 c.825+1G>A, that shows reduced affinity for BMAL1/CLOCK and causes an arrhythmic phenotype. Genotype-phenotype correlation analysis revealed that this variant segregated with ADHD and delayed sleep phase disorder (DSPD) in the affected family. Finally, we found in a phenome-wide association study involving 9438 unrelated adult Europeans that CRY1Δ11 was associated with major depressive disorder, insomnia, and anxiety. These results defined a distinctive group of circadian psychiatric phenotypes that we propose to designate as “circiatric” disorders.
O. Emre Onat, M. Ece Kars, Şeref Gül, Kaya Bilguvar, Yiming Wu, Ayşe Özhan, Cihan Aydın, A. Nazlı Başak, M. Allegra Trusso, Arianna Goracci, Chiara Fallerini, Alessandra Renieri, Jean-Laurent Casanova, Yuval Itan, Cem E. Atbaşoğlu, Meram C. Saka, İ. Halil Kavaklı, Tayfun Özçelik
Plot showing the correlation between sunlight exposure and ADHD severity.