Dominique Bonneau, Luis A Gonzalez-Nieto, Stine Leenskjold, Patrick Callier, Isabelle Thiffault, Katheryn Grand, Pauline Bogaard, Séverine Drunat, Elizabeth J. Bhoj, Hakon Hakonarson, Katherine T. Wild, Elaine H. Zackai, Elena Repnikova, Damien Haye, Irene K Nielsen, Mirena C Astiazaran, Irfan Saadi, Daphné Lehalle, Ida Charlotte Bay Lund, Shivarajan M. Amudhavalli, Annick Toutain, Alain Verloes, Ana Sofia Carvalho, Dong Li, Carol J Saunders, Yoann Vial, Kadri Karaer, The Center for Applied Genomics [Philadelphia, PA, USA], Children’s Hospital of Philadelphia (CHOP ), Division of Human Genetics [Philadelphia, PA, USA], Département de génétique [Robert Debré], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-AP-HP Hôpital universitaire Robert-Debré [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Service de génétique [Tours], Centre Hospitalier Régional Universitaire de Tours (CHRU Tours)-Hôpital Bretonneau, Physiopathologie Cardiovasculaire et Mitochondriale (MITOVASC), Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), University of Coimbra [Portugal] (UC), Equipe GAD (LNC - U1231), Lipides - Nutrition - Cancer [Dijon - U1231] (LNC), Université de Bourgogne (UB)-Institut National de la Santé et de la Recherche Médicale (INSERM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université de Bourgogne (UB)-Institut National de la Santé et de la Recherche Médicale (INSERM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, The Center for Applied Genomics, Neuroprotection du Cerveau en Développement / Promoting Research Oriented Towards Early Cns Therapies (PROTECT), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Robert Debré-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Hôpital Bretonneau-Centre Hospitalier Régional Universitaire de Tours (CHRU Tours), and Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Institut National de la Santé et de la Recherche Médicale (INSERM)
International audience; The SPECC1L protein plays a role in adherens junctions involved in cell adhesion, actin cytoskeleton organization, microtubule stabilization, spindle organization and cytokinesis. It modulates PI3K-AKT signaling and controls cranial neural crest cell delamination during facial morphogenesis. SPECC1L causative variants were first identified in individuals with oblique facial clefts. Recently, causative variants in SPECC1L were reported in a pedigree reported in 1988 as atypical Opitz GBBB syndrome. Six families with SPECC1L variants have been reported thus far. We report here eight further pedigrees with SPECC1L variants, including a three-generation family, and a further individual of a previously published family. We discuss the nosology of Teebi and GBBB, and the syndromes related to SPECC1L variants. Although the phenotype of individuals with SPECC1L mutations shows overlap with Opitz syndrome in its craniofacial anomalies, the canonical laryngeal malformations and male genital anomalies are not observed. Instead, individuals with SPECCL1 variants have branchial fistulae, omphalocele, diaphragmatic hernias, and uterus didelphis. We also point to the clinical overlap of SPECC1L syndrome with mild Baraitser-Winter craniofrontofacial syndrome: they share similar dysmorphic features (wide, short nose with a large tip, cleft lip and palate, blepharoptosis, retrognathia, and craniosynostosis), although intellectual disability, neuronal migration defect, and muscular problems remain largely specific to Baraitser-Winter syndrome. In conclusion, we suggest that patients with pathogenic variants in SPECC1L should not be described as "dominant (or type 2) Opitz GBBB syndrome", and instead should be referred to as "SPECC1L syndrome" as both disorders show distinctive, non overlapping developmental anomalies beyond facial communalities.