ABSTRACT
OBJECTIVES: To test the hypothesis that somatic phosphatidylinositol-4,5-bisphospate 3-kinase, catalytic subunit alpha (PIK3CA) mutations would be found in patients with more common disorders including isolated lymphatic malformation (LM) and Klippel-Trenaunay syndrome (KTS). STUDY DESIGN: We used next generation sequencing, droplet digital polymerase chain reaction, and single molecule molecular inversion probes to search for somatic PIK3CA mutations in affected tissue from patients seen at Boston Children's Hospital who had an isolated LM (n = 17), KTS (n = 21), fibro-adipose vascular anomaly (n = 8), or congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (n = 33), the disorder for which we first identified somatic PIK3CA mutations. We also screened 5 of the more common PIK3CA mutations in a second cohort of patients with LM (n = 31) from Seattle Children's Hospital. RESULTS: Most individuals from Boston Children's Hospital who had isolated LM (16/17) or LM as part of a syndrome, such as KTS (19/21), fibro-adipose vascular anomaly (5/8), and congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (31/33) were somatic mosaic for PIK3CA mutations, with 5 specific PIK3CA mutations accounting for â¼ 80% of cases. Seventy-four percent of patients with LM from Seattle Children's Hospital also were somatic mosaic for 1 of 5 specific PIK3CA mutations. Many affected tissue specimens from both cohorts contained fewer than 10% mutant cells. CONCLUSIONS: Somatic PIK3CA mutations are the most common cause of isolated LMs and disorders in which LM is a component feature. Five PIK3CA mutations account for most cases. The search for causal mutations requires sampling of affected tissues and techniques that are capable of detecting low-level somatic mosaicism because the abundance of mutant cells in a malformed tissue can be low.
Subject(s)
Abnormalities, Multiple , DNA/genetics , Klippel-Trenaunay-Weber Syndrome/genetics , Lymphatic Abnormalities/genetics , Mutation , Phosphatidylinositol 3-Kinases/genetics , Vascular Malformations/genetics , Child , Child, Preschool , Class I Phosphatidylinositol 3-Kinases , Female , High-Throughput Nucleotide Sequencing , Humans , Infant , Klippel-Trenaunay-Weber Syndrome/diagnosis , Klippel-Trenaunay-Weber Syndrome/metabolism , Lymphatic Abnormalities/diagnosis , Lymphatic Abnormalities/metabolism , Male , Phosphatidylinositol 3-Kinases/metabolism , Polymerase Chain Reaction , Vascular Malformations/diagnosis , Vascular Malformations/metabolismABSTRACT
Contexto: A síndrome de Klippel-Trenaunay é uma condição congênita rara caracterizada por uma tríade de anormalidades:malformações capilares, venosas e hipertrofia óssea e de tecidos moles. A gestação em pacientes portadoras dessa síndrome é historicamente desencorajada devido ao possível alto risco obstétrico pela exacerbação da síndrome, havendo apenas 21 casos descritos.Relato de caso: O presente relato apresenta a evolução obstétrica de duas gestantes portadoras de síndrome de Klippel-Trenaunay acompanhadas em São Paulo, Brasil, descrevendo as intercorrências obstétricas, o manejo dessas pacientes e sua evolução. As complicações obstétricas observadas foram: piora da assimetria corporal, sangramento dos hemangiomas cutâneos, fenômenos tromboembólicos, edema importante de membros inferiores. Não foramobservadas complicações fetais. Discussão: As complicações maternas são frequentes e podem estar associadas ao tempo de evolução da síndrome de Klippel -Trenaunay e, principalmente, à gravidade da doença. Embora possa haverexacerbação das manifestações prévias da síndrome, com hemorragia, coagulação intravascular disseminada, eventostromboembólicos e dor, em geral, observam-se complicações menores, cujo manejo conservador permite boa evolução obstétrica, exceção feita a um caso de malformação congênita.Conclusão: Não há evidências com base na literatura preexistente para desencorajar a gestação nessas pacientes. O entendimento da síndrome e cuidado multidisciplinar pré-natal, intra e pós-parto mostram-se fundamentais para o bom desfecho da gestação.
Subject(s)
Humans , Female , Pregnancy , Adult , Congenital Abnormalities/genetics , Pregnancy Complications/etiology , Arteriovenous Malformations/diagnosis , Klippel-Trenaunay-Weber Syndrome/diagnosis , Klippel-Trenaunay-Weber Syndrome/metabolismABSTRACT
AGGF1 is an angiogenic factor, and its deregulation is associated with a vascular malformation consistent with Klippel-Trenaunay syndrome (KTS). This study defines the molecular mechanism for transcriptional regulation of AGGF1 expression. Transcription of AGGF1 starts at two nearby sites, -367 and -364 bp upstream of the translation start site. Analyses of 5'- and 3'-serial promoter deletions defined the core promoter/regulatory elements, including two repressor sites (from -1971 to -3990 and from -7521 to -8391, respectively) and two activator sites (a GATA1 consensus binding site from -295 to -300 and a second activator site from -129 to -159). Both the GATA1 site and the second activator site are essential for AGGF1 expression. A similar expression profile was found for GATA1 and AGGF1 in cells (including various endothelial cells) and tissues. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrated that GATA1 was able to bind to the AGGF1 DNA in vitro and in vivo. Overexpression of GATA1 increased expression of AGGF1. We identified one rare polymorphism -294C>T in a sporadic KTS patient, which is located in the GATA1 site, disrupts binding of GATA1 to DNA, and abolishes the GATA1 stimulatory effect on transcription of AGGF1. Knockdown of GATA1 expression by siRNA reduced expression of AGGF1, and resulted in endothelial cell apoptosis and inhibition of endothelial capillary vessel formation and cell migration, which was rescued by purified recombinant human AGGF1 protein. These results demonstrate that GATA1 regulates expression of AGGF1 and reveal a novel role for GATA1 in endothelial cell biology and angiogenesis.
