Endocannabinoid dysfunction in neurological disease: neuro-ocular DAGLA-related syndrome
Matthew N. Bainbridge, Aloran Mazumder, Daisuke Ogasawara, Rami Abou Jamra, Geneviève Bernard, Enrico Bertini, Lydie Bürglen, Heidi Cope, Ali Crawford, Alexa Derksen, Leon Dure, Emily Gantz, Margarete Koch‐Hogrebe, Anna Hurst, Sonal Mahida, Paige Marshall, Alessia Micalizzi, Antonio Novelli, Hongfan Peng, Diana Rodriguez, Shira L. Robbins, S. Lane Rutledge, Roberta Scalise, Sophia Schließke, Vandana Shashi, Siddharth Srivastava, Isabella Thiffault, Sarah E. Topol, Undiagnosed Disease Network, Maria T. Acosta, Margaret P Adam, David R. Adams, Justin Alvey, Laura M. Amendola, Ashley Andrews, Euan A. Ashley, Mahshid S. Azamian, Carlos A. Bacino, Güney Bademci, Ashok Balasubramanyam, Dustin Baldridge, Jim Bale, Michael J. Bamshad, Deborah Barbouth, Pinar Bayrak‐Toydemir, Anita E. Beck, Alan H. Beggs, Edward M. Behrens, Gill Bejerano, Jimmy Bennet, Beverly Berg-Rood, Jonathan A. Bernstein, Gerard T. Berry, Anna Bican, Stephanie Bivona, Elizabeth Blue, John Bohnsack, Devon Bonner, Lorenzo D. Botto, Brenna Boyd, Lauren C. Briere, Elly Brokamp, Gabrielle Brown, Elizabeth A. Burke, Lindsay C. Burrage, Manish J. Butte, Peter H. Byers, William E. Byrd, John C. Carey, Olveen Carrasquillo, Thomas Cassini, Ta Chen Chang, Sirisak Chanprasert, Hsiao‐Tuan Chao, Gary Clark, Terra R. Coakley, Laurel A. Cobban, Joy D Cogan, Matthew Coggins, F. Sessions Cole, Heather A. Colley, Cynthia M. Cooper, Heidi Cope, William J. Craigen, Andrew B. Crouse, Michael L. Cunningham, Precilla D’Souza, Hongzheng Dai, Surendra Dasari, Joie Davis, Jyoti G. Dayal, Matthew A. Deardorff, Esteban C. Dell’Angelica, Katrina M. Dipple, Daniel Doherty, Naghmeh Dorrani, Argenia L. Doss, Emilie D. Douine, Laura Duncan, Dawn Earl
Abstract
The endocannabinoid system is a highly conserved and ubiquitous signalling pathway with broad-ranging effects. Despite critical pathway functions, gene variants have not previously been conclusively linked to human disease. We identified nine children from eight families with heterozygous, de novo truncating variants in the last exon of DAGLA with a neuro-ocular phenotype characterized by developmental delay, ataxia and complex oculomotor abnormality. All children displayed paroxysms of nystagmus or eye deviation accompanied by compensatory head posture and worsened incoordination most frequently after waking. RNA sequencing showed clear expression of the truncated transcript and no differences were found between mutant and wild-type DAGLA activity. Immunofluorescence staining of patient-derived fibroblasts and HEK cells expressing the mutant protein showed distinct perinuclear aggregation not detected in control samples. This report establishes truncating variants in the last DAGLA exon as the cause of a unique paediatric syndrome. Because enzymatic activity was preserved, the observed mislocalization of the truncated protein may account for the observed phenotype. Potential mechanisms include DAGLA haploinsufficiency at the plasma membrane or dominant negative effect. To our knowledge, this is the first report directly linking an endocannabinoid system component with human genetic disease and sets the stage for potential future therapeutic avenues.