El jueves y viernes 10 y 11 de mayo del 2018 realizamos en la Fundación Ramón Areces un Simposio Internacional, en el cual se trató el tema del mosaicismo somático en malformaciones vasculares.
Juan Carlos López-Gutiérrez - Unidad de Anomalías Vasculares, Hospital Unive...Fundación Ramón Areces
El jueves y viernes 10 y 11 de mayo del 2018 realizamos en la Fundación Ramón Areces un Simposio Internacional, en el cual se trató el tema del mosaicismo somático en malformaciones vasculares.
Rudolf Happle - Dermatología, University of Freiburg Medical Center, Freiburg...Fundación Ramón Areces
El jueves y viernes 10 y 11 de mayo del 2018 realizamos en la Fundación Ramón Areces un Simposio Internacional, en el cual se trató el tema del mosaicismo somático en malformaciones vasculares.
Juan Carlos López-Gutiérrez - Unidad de Anomalías Vasculares, Hospital Unive...Fundación Ramón Areces
El jueves y viernes 10 y 11 de mayo del 2018 realizamos en la Fundación Ramón Areces un Simposio Internacional, en el cual se trató el tema del mosaicismo somático en malformaciones vasculares.
Rudolf Happle - Dermatología, University of Freiburg Medical Center, Freiburg...Fundación Ramón Areces
El jueves y viernes 10 y 11 de mayo del 2018 realizamos en la Fundación Ramón Areces un Simposio Internacional, en el cual se trató el tema del mosaicismo somático en malformaciones vasculares.
Jordi Torren - Coordinador del proyecto ESVAC. Agencia Europea de Medicamento...Fundación Ramón Areces
El martes 5 de junio del 2018 organizamos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre el consumo de antibióticos y transmisión de resistencia entre humanos y animales.
Dominique L. Monnet Director del programa ARHAI (Antimicrobial Resistance an...Fundación Ramón Areces
El martes 5 de junio del 2018 organizamos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre el consumo de antibióticos y transmisión de resistencia entre humanos y animales.
El jueves 24 de mayo del 2018 organizamos una Conferencia con Antonio Cabrales en la Fundación Ramón Areces. Una conferencia en la cual el tema fue: Estilo negociador y confianza, ¿hay diferencias entre hombres y mujeres?
Teresa Puig - Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Espa...Fundación Ramón Areces
El lunes y martes 21 y 22 de mayo del 2018 realizamos un Simposio Internacional en la Fundación Ramón Areces, tratando el tema de la superconductividad y presión: una relación fructífera en el camino hacia la superconductividad a temperatura ambiente.
Elena Bascones - Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Es...Fundación Ramón Areces
El lunes y martes 21 y 22 de mayo del 2018 realizamos un Simposio Internacional en la Fundación Ramón Areces, tratando el tema de la superconductividad y presión: una relación fructífera en el camino hacia la superconductividad a temperatura ambiente.
El jueves 17 de mayo del 2018 se organizó una Mesa Redonda en la Fundación Ramón Areces, en la cual se habló sobre las subidas de tipos en la era Trump y la nueva globalización.
El jueves 17 de mayo del 2018 se organizó una Mesa Redonda en la Fundación Ramón Areces, en la cual se habló sobre las subidas de tipos en la era Trump y la nueva globalización.
El miércoles 16 de mayo del 2018 celebramos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre las nuevas fronteras de investigación sobre la distribución comercial y el comportamiento del consumidor.
El miércoles 16 de mayo del 2018 celebramos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre las nuevas fronteras de investigación sobre la distribución comercial y el comportamiento del consumidor.
Rafael Doménech - Responsable de Análisis Macroeconómico, BBVA Research. Fundación Ramón Areces
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
Nicholas Barr - Profesor de Economía Pública, London School of Economics. Fundación Ramón Areces
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El viernes 27 de abril del 2018 se celebró en la Fundación Ramón Areces una Jornada sobre física , en la cual se trataron diversos temas como: Los materiales mecanocalóricos, magnetísmo, biofísica, la energía oscura y instrumentación astronómica.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Marta Olivares - Investigadora Postdoctoral en Université catholique de Louva...Fundación Ramón Areces
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Víctor R. de la Rosa - Investigador en Universiteit Gent (UGent) y fundador d...Fundación Ramón Areces
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Jordi Torren - Coordinador del proyecto ESVAC. Agencia Europea de Medicamento...Fundación Ramón Areces
El martes 5 de junio del 2018 organizamos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre el consumo de antibióticos y transmisión de resistencia entre humanos y animales.
Dominique L. Monnet Director del programa ARHAI (Antimicrobial Resistance an...Fundación Ramón Areces
El martes 5 de junio del 2018 organizamos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre el consumo de antibióticos y transmisión de resistencia entre humanos y animales.
El jueves 24 de mayo del 2018 organizamos una Conferencia con Antonio Cabrales en la Fundación Ramón Areces. Una conferencia en la cual el tema fue: Estilo negociador y confianza, ¿hay diferencias entre hombres y mujeres?
Teresa Puig - Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Espa...Fundación Ramón Areces
El lunes y martes 21 y 22 de mayo del 2018 realizamos un Simposio Internacional en la Fundación Ramón Areces, tratando el tema de la superconductividad y presión: una relación fructífera en el camino hacia la superconductividad a temperatura ambiente.
Elena Bascones - Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Es...Fundación Ramón Areces
El lunes y martes 21 y 22 de mayo del 2018 realizamos un Simposio Internacional en la Fundación Ramón Areces, tratando el tema de la superconductividad y presión: una relación fructífera en el camino hacia la superconductividad a temperatura ambiente.
El jueves 17 de mayo del 2018 se organizó una Mesa Redonda en la Fundación Ramón Areces, en la cual se habló sobre las subidas de tipos en la era Trump y la nueva globalización.
El jueves 17 de mayo del 2018 se organizó una Mesa Redonda en la Fundación Ramón Areces, en la cual se habló sobre las subidas de tipos en la era Trump y la nueva globalización.
El miércoles 16 de mayo del 2018 celebramos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre las nuevas fronteras de investigación sobre la distribución comercial y el comportamiento del consumidor.
El miércoles 16 de mayo del 2018 celebramos una Jornada en la Fundación Ramón Areces, en la cual se habló sobre las nuevas fronteras de investigación sobre la distribución comercial y el comportamiento del consumidor.
Rafael Doménech - Responsable de Análisis Macroeconómico, BBVA Research. Fundación Ramón Areces
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
Nicholas Barr - Profesor de Economía Pública, London School of Economics. Fundación Ramón Areces
El martes 8 de mayo de 2018 realizamos una conferencia en la Fundación Ramón Areces, en la cual se habló sobre el futuro de las pensiones: una visión global.
El viernes 27 de abril del 2018 se celebró en la Fundación Ramón Areces una Jornada sobre física , en la cual se trataron diversos temas como: Los materiales mecanocalóricos, magnetísmo, biofísica, la energía oscura y instrumentación astronómica.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Marta Olivares - Investigadora Postdoctoral en Université catholique de Louva...Fundación Ramón Areces
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Víctor R. de la Rosa - Investigador en Universiteit Gent (UGent) y fundador d...Fundación Ramón Areces
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
El viernes 20 de abril organizamos una Jornada sobre la ciencia en el corazón de Europa, en colaboración con Científicos Españoles en Bélgica (CEBE) y realizada en la Fundación Ramón Areces.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Astronomy Update- Curiosity’s exploration of Mars _ Local Briefs _ leadertele...
Víctor Martínez-Glez. - Instituto de Genética Médica y Molecular (INGEMM). IdiPAZ, Hospital Universitario La Paz, Madrid, España.
1. Overview of somatic
mosaicism in vascular
malformations
Victor Martinez-Glez
Vascular Malformations Section
Institute of Medical and Molecular Genetics (INGEMM)
La Paz Hospital - Madrid
International Symposium
Somatic Mosaicism in Vascular Malformations
5. • Most vascuar malformations are identified by history and physical
examination
• Imaging and histopathology are useful for atypical cases
• Clinical heterogeneous
• Variable response to treatment (mainly sirolimus in LM)
• Resection, laser, scleroterapy, and/or embolization
• Control
• Common progression and recurrence
• Mosaicism
Diagnosis
40. MOSAICISM & NGS
Study of variants in somatic mosaicism
Validation of candidate variants
Sanger (>20%) Pyrosequencing (>5%) ddPCR (>0,1%)
41. EVALUATION OF MOSAIC VASCULAR ANOMALIES
• Classification
• Mosaicism
• Embryology / Timing
• Gene / Pathway / Expression / Lethality
• Location / distribution
• Second Hit
• Samples, testing, analysis
42. • Mosaicism classification
• Vascular malformations - Clinical classification
– Controversies / recent advances
– Are all capillary malformations the same?
– Histopathology
• Vascular malformations associated with other
anomalies
– Combined vascular and non-vascular mosaic anomalies
– Classification, taxonomy
• Genotyping and phenotyping
– Samples, detection, and bioinformatic challenges
• Research
– Functional Studies
– Animal models
– Editing tools
• Genetic counselling
CHALLENGES
43. Acknowledgements
Vascular Malformations Section (MALVA)
Lara Rodríguez-Laguna,
BSc. MSc.
Gema Gordo,
BSc. MSc.
Dr. Pablo Lapunzina
INGEMM Coordinator
Dr. Juan Carlos Lopez-Gutierrez
Vascular Anomalies Unit Coordinator
Bioinformatics Section (INGEMM)
Genomics Section (INGEMM)
Noelia Agra,
BSc. PhD.
Dr. Marta Feito
Dermatology Dept.
Victor Martinez-Glez,
MD. PhD.
Editor's Notes
Hi again. In the previous presentation we have seen how today we know that individuals are indeed complex mosaics with multiple genotypes acquired from embryonic development to adulthood. In the field of vascular anomalies, the increasing detection of low mosaic mutations in new or known genes demands a change in the model of approaching patients and research. I am going to make a small overview of somatic mosaicism in vascular malformations, reviewing some concepts that may be useful for the rest of the symposium.
Let’s start by defining vascular anomalies, which comprise a heterogeneous group of disorders characterized by abnormal growth or development of blood or lymphatic vessels. Since the diagnosis of vascular anomalies is often challenging due to the large variety of conditions with a wide range of clinical manifestations and severity, a classification of all these anomalies was necessary. The first classification of vascular anomalies is from 1982, and divided benign vascular anomalies into hemangiomas and vascular malformations.
This classification was later adopted by the International Society for the Study of Vascular Anomalies (ISSVA) in 1996 and modified to categorize vascular anomalies as vascular tumors or vascular malformations. Vascular tumors are characterized by the abnormal proliferation of endothelial cells and aberrant blood vessels. In contrast, vascular malformations are networks of abnormal vessels that form during fetal development and have normal endothelial cell turn over. The most recent version of this classification is from 2014, where new knowledge was incorporated.
Thus, focusing on the vascular malformations, which are the subject of this symposium, these are basically classified by the type of structure involved (arterial, capillary, venous or lymphatic) and the malformation hemodynamics (high-flow or low-flow), each one with different specific presentations. On the other hand, we have the combined malformations, those of major named vessels, those associated with other non-vascular anomalies, and a section for those not classified in any of these sections.
Simplified terminology and classification have improved consistency in the diagnosis of vascular anomalies. Of course, is not exempt from failures and shortcomings, some of which will probably be solved at the next ISSVA congress within 3 weeks. And this is an important problem because issues such as natural history, including age at onset and progression, and genetic counseling may vary considerably depending on the phenotype, the genetic cause and the inheritance pattern.
In clinical practice, there are vascular malformations with a typical clinical course, easy to diagnose on physical exam, while others are atypical, maybe deep lesions involving vital structures for which clinical diagnosis is unclear or insufficient. Imaging studies and Histopathology are then essential for an accurate diagnosis. There is also a variable response to treatment (mainly sirolimus in LM) and the surgical approach is usually by resection, laser, scleroterapy, and embolization, but in many cases a follow-up attitude is simply maintained without intervention, either due to the mild compromise, or precisely because of the contrary.
What is clear today is that somatic mosaicism is an essential part of the pathogenesis and phenotype of vascular malformations, explaining both the clinical variability and the difficulty in discovering the genes that cause each pathology.
So let's see a bit of the history of how mosaicism in vascular malformations was discovered. I will not mention all of them, but I will mention some of the works that have brought us here today. I already mentioned that the first classification is from 1982.
And two years later, the first gene associated to a VascM was discovered. Germline mutations in Endoglin gene causes Hereditary hemorrhagic telangiectasia (HHT), characterized by multiple arteriovenous malformations that lack capillaries, resulting in direct connections between arteries and veins. This causes epistaxis and Telangiectases most evident on the lips, tongue, buccal mucosa, face, chest, and fingers. Mutations in ENG are found constitutively, and today, other 3 genes has been associated with HHT, all within the transforming growth factor signaling pathway.
In 1986 this paper described that germline mutations in the TEK gene were present in patients with familial venous malformations. These mutations in TEK, which codes for the tyrosine kinase receptor TIE2, cause gain of function on this protein, that is critical for communication of endothelial and smooth muscle cell in venous morphogenesis. As we will see later, this gene is very interesting and will serve as an example to show the etiopathogenic and phenotypic complexity generated by somatic mosaicism.
In 1988, the first gene causing lymphedema, the FLT4 gene, was discovered. Lymphedema, more than a malformation by itself, is the consequence of alterations in the lymphatic system. Leaving aside the lymphedema generated as a result of cancer treatment or due to trauma or infections, the number of pathologies with a genetic cause that are mainly characterized by lymphedema, or in which the lymphedema is part of a syndromic pathology, is extensive and several causing genes are known. However, many patients remain without molecular diagnosis in these pathologies. The genetic causes of lymphedema so far are germline mutations, either inherited or de novo.
An important part of vascular malformations are due to alterations in the endothelial cells. However, in Glomuvenous malformations (GVM), caused by germline mutations in glomulin, the affected cell type is the vascular smooth muscle cells.
That as we see here, they are part of the structure of the capillary vessels. Thus, GVM represents one clear example demonstrating the link between different cell types involved in the development of vascular malformations.
In 2003 this work described that the CM and associated arteriovenous malformations, can be caused by germline heterozygous and inactivating mutations in RASA1 gene. This gene facilitates the inactivation of Ras pathway. Thus, loss of RASA1 function amplifies RAS downstream signalling, with numerous consequences, including aberrant proliferation and angiogenesis
This work does not address a discovery itself, but helped to delineate the spectrum of VascM associated with the PTEN gene. This oncogene was already known for its involvement in cancer and for causing the Bannayan-Riley-Ruvalcaba and Cowden syndromes. Although VascM are not a main characteristic, these patients do present vascular malformations. This work described that those vascular anomalies in patients with a germline PTEN mutation are typically multifocal and intramuscular combinations of fast-flow channels and ectopic fat. But, beyond that, this work helped us to understand the molecular mechanisms of VascMs when associated with other genetic syndromes. For example, this might be used to understand how different genes from the same molecular pathway associates common alterations in fatty tissue, overgrowth and VascMs.
Something that is also evident in the Proteus syndrome. And here we come to 2011, the awakening of the discovery of genetic causes in somatic alterations associated with VascM, thanks to the use of high-throughput technologies able to detect small fractions of mutated alleles within a tissue sample. This paper shows how activating mutations in the AKT1 gene are detected in different tissues and cell lines in mosaics ranging from 1 to almost 50%. Remember that 50% would be an heterecigote state and therefore the mutation would be present in all cells. Here we must highlight something important, mutations in Proteus are not only seen in a somatic mosaic, that is, in the affected tissues, but also those mutations are not found in germinal state. This will serve to talk later about the concept of lethality.
That same year, the use of drugs aimed at specific molecular targets, specifically rapamycin, an inhibitor of mTOR, which as we see here acts downstream AKT, was already being tested for Vascular Anomalies. Unfortunately, the experience with this promising drug is still scarce and it is not known why there are patients with a good response and others not. Some new drugs on these same molecular pathways are currently being tested.
And here we have the pop star in the world of vascular mosaics, the PIK3CA gene. Detected in affected tissues from patients with complex syndromes mainly associated with overgrowth, either megalencephaly or lipomatous overgrowth. Syndromes in which the VascM are also characteristic. I will talk more about this gene later.
Before I mentioned that germline TEK mutations were described in 1986 as a cause of familial venous malformations. In this work in 2013, somatic mutations of this same gene were detected in sporadic venous malformations. But this will become more interesting a few years later as I will comment soon.
By 2015, the number of apparently unrelated pathologies, caused by PIK3CA, was already large. Here we see that somatic and activating mutations in PIK3CA are also related to both isolated LM and to syndromes in which LM are a major component.
So it was necessary to put some order. This work proposed to include all alterations caused by PIK3CA under the term PROS. Diagnostic criteria and guidelines for molecular diagnosis were also established. This figure shows very well, for each pathology, the relationship between phenotypic severity and distribution, as a consequence of the specific time and place during the embryonic development in which the mutation arose. One of the main concepts of somatic mosaicism.
Fortunately, not all publications are based on molecular discoveries. There are still some, and necessary works, in which important clinical patterns are provided, something that far from being closed, still has much to explore and is important in terms of classification and diagnosis.
Of course, there are also works oriented to give recommendations for genetic testing, like this one for the PROS spectrum.
Last year somatic mutations were described in this gene, GNA11, important in the diagnosis of another clinical entity called DCMO. As its name suggests, it is a somewhat diffuse clinical classification, and will also be discussed in this symposium.
Now, here comes the most interesting part of the TEK gene. In this work Authors identified mosaic double (cis) mutations (that is, two somatic mutations on the same allele) in the TEK gene as the principal cause of BRBN.
But the interesting thing about this work is on this figure, where authors show different types of mutations according to the different possible phenotypes of the venous malformations associated with this gene. Familial venous malformations are caused by a somatic mutation in a patient who already had a germline mutation. Unifocal VMs are caused by unique somatic mutations, but with more severe effects on the protein function than those found in germinal cases. The multifocal venous malformations show two somatic mutations and the BRBN has double mosaic (cis) mutations. With this, the complexity of the second hit concept within the mosaicism is clearly exposed.
To end with this timeline, two more publications from this year, 2018. This first one, in which mutations in PIK3CA are also described for CLAPO syndrome. This article raised the question of whether we should continue calling each of the syndromes caused By PIK3CA by their original name or whether it would be better to call them all as PROS. In this way, the controversy genotype only or only on phenotype only classifications re-emerged. This topic will also be addressed in this symposium.
Finally, this most recent publication, in which authors detected multiple mosaic-activating variants in 4 genes of the RAS/MAPK pathway, a pathway commonly activated in cancer and also known as causing the RAS-opathies, another group of genetic developmental syndromes.
So what have we learned?
On the one hand, we can see how the genes that cause VascMs are grouped in a few molecular pathways that are also quite related to each other. On the other, that the elucidation of the genetic causes of vascular malformations found in inherited syndromes, as well as the identification of specific somatic mutations in both inherited and sporadic forms, has played an invaluable role in understanding normal and pathological blood vessel structure and function. The biochemical connections between these pathways might also suggest that at least in some cases, therapies developed for one type of vascular malformation might show some efficacy for others.
In addition, returning to the concept of mosaicism, we have learned that the specific characteristics of a VascM depends, among other things, on the number of affected cells, on the moment of the embryonic development in which the mutation arose, and on its specific location.
So, as we see in the figure of this paper, an important consideration is that somatic mutations occur in different cell types and tissues as well as in different developmental stages. Mutations in GNAQ causes non-syndromic Port-wine stains, but also the Sturge-Weber syndrome, a severe neurocutaneous disorder. Nevertheless, both conditions likely affect the same cell types (the, endothelial cells). The milder phenotype of the birthmarks could result from a later developmental origin of the mutation. Also, mutations in GNAQ, when occurring in melanocytes later in life, is a frequent driver mutation in uveal melanoma.
Other mosaic mutations also differ in their clinical importance based on cell or tissue-specific involvement. McCune-Albright syndrome (OMIM #174800) is caused by somatic activating mutations in GNAS which is expressed biallelically through most of the body, but the maternal allele is imprinted in particular tissues such as the pituitary, and progressive osseous heteroplasia and pseudopseudohypoparathyroidism result from loss of function mutations in the paternal allele.
Here, somatic AKT1 mutations are associated with cancer and Proteus syndrome. The AKT2 gene is associated with diabetes. And Somatic mutations in AKT3 cause a specific Megalencephaly syndrome. This genes have specific tissue expression, thus highlight the complex interaction of localized somatic mutation with tissue or cell-specific gene expression and signaling pathways.
We have also learned that the concept of mosaicism is not always easy to understand. For example, what is affected tissue? Let's look at this example. The somatic mutations of the GNAQ gene cause 87% of the sporadic or syndromic CM, and when studying an affected tissue, the pathogenic variant can be detected in mosaics that vary between 1 and 22%, but if we look a little more closely, in fact that mutation is concentrated in the endothelial cells and not in the rest of the components of the capillary vessels. Actually, within the endothelial cells there are also percentages of mosaicism. Theoretically, a given mutation can be present in all cell types of the body but not in all the cells. Explain this is somewhat more complicated.
We have also learned about the importance of the specific function of the affected gene. The expression or cellular localization of the PIK3CA gene with another gene such as GATA2 is not comparable ammosng different tissues,
Another important concept learned is that of lethal genes. As early as 1987, Dr. Happle proposed that mutated genes not compatible with life in germinal form can only be found in the somatic mosaicism, and proposed a series of syndromes in which this mechanism was highly probable.
30 years later, Dr. Happle published this work on the classification of cutaneous mosaicism in which he reviewed the works confirming this concept.
In addition to the TEK gene, the second hit hypothesis has been demonstrated in the genes associated with CCM or RASA1. Also, if we look at the glomovenous malformations, the second hit can also be a uniparental isodisomy, so in genetic terms we have also learned that there are more things besides strictly genic variations.
We have also seen how gain-of-function mutations are mainly associated with somatic mosaicism, while loss-of-function mutations are more frequent in the germ line or in the cases of second hit.
Although this figure would not win a graphic design award, while preparing this talk I thought that maybe it could serve to visualize several of these concepts at the same time, just to demonstrate the complexity of this type of malformations. The VEGF pathway is more associated with germline mutations causing lymphatic malformations, the genes with gain of function to mosaicism, and in some cases we can find genes with different patterns. So there are many conditions that must be taken into account in each case.
The graphic was ugly, yes, but the table version is even worse. But as I did it, I'm showing it to you.
So what all this means for the patient? First, we must take into account these concepts in order to recognize different alterations and what they mean, such as why the midline capillary malformations in the lower lip and lower lip are embryologically different and therefore have different consequences.
Or that we should recognize a mosaic pattern to study the right sample in each patient and the parents.
And that it is important to know which technique will allow us to detect genetic alterations in low mosaics.
Therefore, all these concepts are important when evaluating a patient.
But we still have many challenges to solve. In future talks of this symposium we will talk about how mosaicism in general still needs an adequate classification, as well as the classification of vascular malformations, which has important controversies, we will talk specifically about CM. Non-vascular manifestations and conflicts regarding taxonomy will also be discussed. We will also review the associations between phenotype and genotype, as well as the difficulty in diagnosis, including the bioinformatic challenges of the analysis of massive data for the search of low mosaics. Then we will immerse ourselves in the world of functional studies. For example, in vivo models can help to uncover the secrets of the development of vascular malformation. We will also see what can offer us the new techniques of gene editing in the somatic pathologies. Finally, as it can not be otherwise, the challenges of the somatic mosaicism in the genetic counseling will also be discussed.
I want to thank all the people I work with every day, and all of you for being here today.