The main goal of the study is to evaluate the safety and efficacy of GTX-102 in participants with Angelman Syndrome.

Autism spectrum disorder (ASD) , hereafter referred to as autism, is a group of neurodevelopmental disorders caused by genetic and environmental factors. Its core symptoms are social impairment, repetitive stereotyped behaviors, and restricted interests.

The 15q11-13 region of the human chromosome is a locus prone to structural abnormalities leading to neurological disorders. Maternal duplications within this region lead to Dup15q syndrome , which accounts for approximately 1% of ASD cases .

This region harbors multiple alleles, and current research indicates that the pathophysiological alterations in this syndrome primarily involve UBE3A . Among all genes in the 15q11-13 region, only UBE3A exhibits cell-type-specific maternal monoallelic expression . Consequently, duplication of the UBE3A gene is considered the primary pathogenic factor in the pathology of Dup15q syndrome.

Studies show that the metabolic conversion of retinol to retinoic acid is impaired in ASD patients with UBE3A overexpression and corresponding animal models . Notably, dietary supplementation with all-trans retinoic acid (ATRA) has been shown to significantly ameliorate autism-like behaviors caused by UBE3A overexpression in male mice .

This study aims to evaluate ATRA treatment in children with Dup15q syndrome-related autism , assessing changes in their ADOS-2 scores , to potentially provide a novel therapeutic approach for autism treatment.

The purpose of this study is to evaluate the safety and efficacy of MVX-220 gene therapy in children and adults with Angelman syndrome with UBE3A gene deletion, uniparental disomy, or imprinting center defect genotypes.

Silver Russell Syndrome (SRS) is a rare imprinting disorder (about 1/16000). Parental imprinting is an epigenetic regulation phenomenon leading to the monoallelic expression of some genes. Its establishment takes place in the gametes and its maintenance is important at the early embryonic stage. Increase in the prevalence of conception by assisted reproductive technology (ART) has already been found in patients with imprinted disorder such as Angelman, Beckwith-Wiedemann or Prader Willi Syndromes, and more recently with SRS; ART is associated with an increase in the frequency of SRS. Several hypotheses are formulated to explain this increase. The first one is the involvement of the infertility etiology in the imprinting disorder genesis. The second one is the involvement of ART technics in the genesis of abnormal gamete imprinting during their manipulation or during imprinting maintenance at early embryonic stages.

Our main objective is to estimate ART conceptions prevalence in children followed for a SRS. The secondary objectives are to estimate infertility prevalence among parents of patients with SRS, to estimate factors frequency possibly responsible for the genesis of imprinting anomalies among parents of patients with SRS, to describe the infertility causes and to detail ART technics used (stimulation protocols, type of fertilization used, modality of embryonic culture and transfer, embryonic characteristics).

A transversal pilote study will be firstly conducted in parents of patients followed in Silver Russell Syndrome Reference Center (Pediatric Endocrine department, in Trousseau Hospital, Paris).

Data collection will be done by phone, after collecting the non-opposition of the parents, in order to complete a questionnaire concerning their fertility and conception mode of their child. If ART was used to conceive, a questionnaire concerning the details of the ART technics used will be sent to the doctor and:or the ART biologist, who performed the ART. The data will be anonymized and collected on a REDCap database.

The purpose of this study is to evaluate the efficacy and safety of ION582 in children and adults with Angelman syndrome caused by a deletion or mutation of the UBE3A gene.

Angelman syndrome (AS) is a rare neurogenetic disorder that affects approximately 1 in 15,000 children - approximately 500,000 people worldwide. It is a major neurodevelopmental disorder characterized by severe developmental delay with significant intellectual disability, lack of oral language, motor, balance, and sensory impairments.

While basic research and clinical trials are progressing, the scientific community is still searching for key biomarkers to assess significant improvements in individuals participating in clinical trials.

Eye tracking has been widely used in the diagnosis of social perception abnormalities in children with autism spectrum disorder, as has already been the case for other rare neurodevelopmental diseases. However, few studies have highlighted the usefulness of eye tracking as a diagnostic tool for social behavioral disorders in individuals with Angelman syndrome. Given the prevalence of autistic-like symptoms in patients with AS, if eye-tracking can identify abnormalities in social perception in children with Angelman syndrome, these measurements could become a biomarker for therapeutic studies in these patients.