**Background:** Robin sequence (RS) is a congenital condition defined by micrognathia, glossoptosis, and upper airway obstruction. It is highly variable, ranging from mild to life-threatening airway obstruction. Untreated obstruction can lead to hypoxemia, growth failure, cognitive deficits, and cor pulmonale. Prevalence is estimated at 1:8,500 to 1:14,000. About 80% of patients have a cleft palate, and half have isolated RS while the rest have associated syndromes. Treatment options include non-surgical (prone positioning, CPAP, nasopharyngeal airway, orthodontic plates) and surgical (tongue-lip adhesion, mandibular distraction osteogenesis, tracheostomy). Due to the rarity of RS, randomized controlled trials are not feasible, making registry data essential for comparing treatments and understanding long-term outcomes.
**Methods:** This is a prospective, observational, noninterventional, multicenter, multinational registry. Patient enrollment began in January 2022. Eligible patients are all those diagnosed with RS (isolated or syndromic), irrespective of treatment, with informed consent from legal guardians. Maximum age at enrollment is 12 months. The registry uses the Castor Electronic Data Capture System, which is GDPR-compliant and ISO 27001 certified. Data are entered pseudonymized by physicians and academic staff. The core dataset includes modules on RS phenotype, demographics, pre- and postnatal data, family history, clinical signs, diagnostics, therapy, adverse events, nutrition, short-term outcome at discharge, and follow-up visits. Data entry is designed to take no longer than 15 minutes per patient. The registry is open to any hospital treating children with RS; four initial European centres (London, Paris, Amsterdam, Tübingen) launched it, each applying a different treatment modality. Follow-up is according to each centre's standard practice. Planned analyses include descriptive statistics, regression/logistic models, and propensity score analysis if sufficient patients per treatment group are enrolled.
**Key Results:** As a protocol paper, no results are presented. The registry was launched in January 2022, and the first patient was enrolled that same month. First interim analyses are planned after inclusion of 10 patients per study centre, expected after about two years. The registry is long-term and open-ended, intended to evolve with emerging research questions.
**Clinical Implications:** This registry is the first to include all RS patients regardless of treatment, allowing comparison of outcomes across different therapeutic approaches. It will provide longitudinal data on neurocognition, growth, speech development, hearing, and quality of life. The data may help generate clinical guidelines, personalize treatment, and inform health policy. The registry also strengthens international collaboration among RS experts. Limitations include potential variability in data quality and completeness due to different clinical settings, which will be addressed through regular inter-centre exchanges and development of data entry standards.