PT - JOURNAL ARTICLE AU - Lara Rodriguez-Laguna AU - Kristina Ibañez AU - Gema Gordo AU - Sixto Garcia-Minaur AU - Fernando Santos-Simarro AU - Noelia Agra AU - Elena Vallespín AU - Victoria E Fernández-Montaño AU - Rubén Martín-Arenas AU - Ángela del Pozo AU - Héctor Gonzalez-Pecellín AU - Rocío Mena AU - Inmaculada Rueda-Arenas AU - María V. Gomez AU - Cristina Villaverde AU - Ana Bustamante AU - Carmen Ayuso AU - Víctor L. Ruiz-Perez AU - Julián Nevado AU - Pablo Lapunzina AU - Juan C. Lopez-Gutierrez AU - Victor Martinez-Glez TI - CLAPO syndrome: Identification of somatic activating <em>PIK3CA</em> mutations and delineation of the natural history and phenotype AID - 10.1101/154591 DP - 2017 Jan 01 TA - bioRxiv PG - 154591 4099 - http://biorxiv.org/content/early/2017/06/26/154591.short 4100 - http://biorxiv.org/content/early/2017/06/26/154591.full AB - Background CLAPO syndrome is a rare vascular disorder characterized by Capillary malformation of the lower lip, Lymphatic malformation predominant on the face and neck, Asymmetry, and Partial/generalized Overgrowth. Although the genetic cause is not known, the tissue distribution of the clinical manifestations in CLAPO seems to follow a pattern of somatic mosaicism.Subjects and methods We clinically evaluated a cohort of 13 patients with CLAPO and screened 20 DNA blood/tissue samples from nine patients using high-throughput, deep sequencing.Results We identified five activating mutations in the PIK3CA gene in affected tissues from six of the nine patients studied; one of the variants (NM_006218.2:c.248T&gt;C; p.Phe83Ser) has not been previously described in developmental disorders.Conclusions We describe for the first time the presence of somatic activating PIK3CA mutations in patients with CLAPO. We also report an update of the phenotype and natural history of the syndrome.