GenIDA: an international participatory database to gain knowledge on health issues related to genetic forms of neurodevelopmental disorders

International audienceIntellectual disability with or without manifestations of autism and/or epilepsy affects 1–2% of the population, and it is estimated that more than 30–50% of these cases have a single genetic cause. More than 1000 genes and recurrent chromosomal abnormalities are involved in these genetic forms of neurodevelopmental disorders, which often remain insufficiently described in terms of clinical spectrum, associated medical problems, etc., due to their rarity and the often-limited number of patients’ phenotypes reported. GenIDA is an international online participatory database that aims to better characterise the clinical manifestations and natural histories of these rare diseases. Clinical information is reported by parents of affected individuals using a structured questionnaire exploring physical parameters, cognitive and behavioural aspects, the presence or absence of neurological disorders or problems affecting major physiological functions, as well as autonomy and quality of life. This strengthens the implication in research of the concerned families. GenIDA aims to construct international cohorts of significant size of individuals affected by a given condition. As of July 2022, GenIDA counts some 1545 documented patient records from over 60 nationalities and collaborates with clinicians and researchers around the world who have access to the anonymized data collected to generate new, medically meaningful information to improve patient care. We present the GenIDA database here, together with an overview of the possibilities it offers to affected individuals, their families, and professionals in charge of the management of genetic forms of neurodevelopmental disorders. Finally, case studies of cohorts will illustrate the usefulness of GenIDA

Calcium Rubies: a family of red-emitting functionalizable indicators for two-photon Ca2+ imaging.

International audienceCalcium Rubies, a family of functionalizable BAPTA-based red-fluorescent calcium (Ca2+) indicators, were designed and synthesized as new tools for intracellular Ca2+ imaging. The attachment of a side arm on the ethylene glycol bridge makes it possible to link the indicator to various groups while leaving open the possibility of aromatic substitutions on the BAPTA core for tuning the Ca2+ binding affinity. Using this approach it has been possible to characterize three different CaRubies having affinities between 3 and 22 µM. Using click chemistry, we demonstrate high-yield linkage of the azido form of their arm to PEG molecules that can be used, e.g. the stoichiometric design of ratiometric, FRET-based indicators. The long excitation and emission wavelengths of CaRubies allow otherwise challenging multi-color experiments, e.g., when combining Ca2+ uncaging or optogenetic stimulation with Ca2+ imaging. We illustrate this capacity by the detection with CaRubies of blue-light-evoked Ca2+ transients in cultured astrocytes expressing CatCh, a light-sensitive Ca2+-translocating channelrhodopsin, linked to yellow fluorescent protein for the identification of transfected cells. Using time-correlated single-photon counting, we measured fluorescence lifetimes for all CaRubies and show a roughly tenfold increase in the average lifetime upon Ca2+ chelation. Since only the fluorescence quantum yield of the CaRubies is Ca2+-dependent, calibrated measurements of absolute Ca2+ concentrations are possible with single-wavelength two-photon fluorescence excitation

The ESMERALDAS experiment offshore-onshore North Ecuador-South Colombia: investigations on margin segmentation and earthquake generation

The Nazca plate converges toward the South American plate along a ~E-W direction at a rate of about 6 cm/yr. This process in northern Ecuador - southern Colombia has produced 4 megathrust earthquakes during the last century. The 500 km long rupture zone of the 1906 event (Mw = 8.8) was partially reactived by 3 thrust events occurring in 1942 (Mw = 7.8), 1958 (Mw = 7.7) and 1979 (Mw = 8.2), which rupture zones abut one other. Marine geophysical data acquired during the last decade experiments (SUBLIME, 1998; SISTEUR, 2000 and SALIERI, 2001), among which seismicity, bathymetry, multichannel seismics and wide-angle data, image the tectonic structures of the margin and evidence that the overriding oceanic margin is segmented by trans- verse crustal faults, that potentially correlated with the limits of the major coseismic slip zones. From February to June 2005, we carried out the ESMERALDAS experi- ment in order to 1- characterize the 3D seismic structure of the margin and identify the velocity heterogeneities associated with the transverse accident and asperities, and 2- obtain the best possible hypocentral locations and focal mechanisms. These infor- mations will be used to identify the deformation style of the active tectonic features observed in the multichannel seismic profiles and, in turn, to characterize the global geodynamic setting of the area. The further objective is to better understand the gener- ation and propagation mechanisms of the four large earthquakes that affected this part of the margin during the last century. This project is an active collaboration between France, Ecuador, Colombia and Spain. Field-work was done in cooperation with the Instituto Jaume Almera and the Unidad Tecnologica del Mar of Barcelona, Spain, the Instituto Geofisico de la Escuela Politecnica Nacional of Quito, Ecuador, the Instituto Oceanografico de la Armada of Guayaquil, Ecuador and the Instituto de Geologia y Minera of Bogota, Colombia. The experiment consists in the deployment of 2 seismo- logical networks (including broad-band stations): 34 3-components portable stations were installed on land and 26 3-components Ocean Bottom Seismometers were dis- tributed offshore. Other stations of the permanent local networks complemented our temporary network. Two different periods characterized the ESMERALDAS exper- iment. During the first period, the french R/V L'Atalante surveyed the study area, collecting underway geophysics and shooting large Air-Gun shots that were recorded by the two networks. In the second period, the networks has been kept in place until beginning of June to record the natural seismicity.The OBS network was retrieved us- ing the colombian R/V Providencia . Gravimetry analysis clearly illustrates the margin segmentation. Due to complexity of seismic data processing, wide-angle results will be presented later-on this year.Peer Reviewe

Calcium Rubies: A Family of Red-Emitting Functionalizable Indicators Suitable for Two-Photon Ca²⁺ Imaging

We designed Calcium Rubies, a family of functionalizable BAPTA-based red-fluorescent calcium (Ca²⁺) indicators as new tools for biological Ca²⁺ imaging. The specificity of this Ca²⁺-indicator family is its side arm, attached on the ethylene glycol bridge that allows coupling the indicator to various groups while leaving open the possibility of aromatic substitutions on the BAPTA core for tuning the Ca²⁺-binding affinity. Using this possibility we now synthesize and characterize three different CaRubies with affinities between 3 and 22 μM. Their long excitation and emission wavelengths (peaks at 586/604 nm) allow their use in otherwise challenging multicolor experiments, e.g., when combining Ca²⁺ uncaging or optogenetic stimulation with Ca²⁺ imaging in cells expressing fluorescent proteins. We illustrate this capacity by the detection of Ca²⁺ transients evoked by blue light in cultured astrocytes expressing CatCh, a light-sensitive Ca²⁺-translocating channelrhodopsin linked to yellow fluorescent protein. Using time-correlated single-photon counting, we measured fluorescence lifetimes for all CaRubies and demonstrate a 10-fold increase in the average lifetime upon Ca²⁺ chelation. Since only the fluorescence quantum yield but not the absorbance of the CaRubies is Ca²⁺-dependent, calibrated two-photon fluorescence excitation measurements of absolute Ca²⁺ concentrations are feasible

Loss-of-Function Mutations in RSPH1 Cause Primary Ciliary Dyskinesia with Central-Complex and Radial-Spoke Defects

International audiencePrimary ciliary dyskinesia (PCD) is a rare autosomal-recessive respiratory disorder resulting from defects of motile cilia. Various axonemal ultrastructural phenotypes have been observed, including one with so-called central-complex (CC) defects, whose molecular basis remains unexplained in most cases. To identify genes involved in this phenotype, whose diagnosis can be particularly difficult to establish, we combined homozygosity mapping and whole-exome sequencing in a consanguineous individual with CC defects. This identified a nonsense mutation in RSPH1, a gene whose ortholog in Chlamydomonas reinhardtii encodes a radial-spoke (RS)-head protein and is mainly expressed in respiratory and testis cells. Subsequent analyses of RSPH1 identified biallelic mutations in 10 of 48 independent families affected by CC defects. These mutations include splicing defects, as demonstrated by the study of RSPH1 transcripts obtained from airway cells of affected individuals. Wild-type RSPH1 localizes within cilia of airway cells, but we were unable to detect it in an individual with RSPH1 loss-of-function mutations. High-speed-videomicroscopy analyses revealed the coexistence of different ciliary beating patterns—cilia with a normal beat frequency but abnormal motion alongside immotile cilia or cilia with a slowed beat frequency—in each individual. This study shows that this gene is mutated in 20.8% of individuals with CC defects, whose diagnosis could now be improved by molecular screening. RSPH1 mutations thus appear as a major etiology for this PCD phenotype, which in fact includes RS defects, thereby unveiling the importance of RSPH1 in the proper building of CCs and RSs in humans