Sjögren syndrome (SS) in adults is characterised by inflammation of the exocrine glands, principally the salivary and lacrimal glands resulting in xerostomia (dry mouth) and xerophthalmia (dry eyes).It can also present with more extensive exocrinopathy as well as extra-glandular, systemic features.

SS is defined as primary SS (pSS) when it occurs in isolation, and as secondary SS, if associated with other autoimmune conditions. The incidence and prevalence rates of SS vary depending on the population. To date, there have been no studies reporting accurate incidence or prevalence of SS in childhood. Childhood onset SS defined as disease diagnosed before 18 years of age is believed to be rare; however, it is likely it is under-recognised and therefore under-diagnosed.

The overarching aim of this study is to identify epidemiological, clinical and laboratory characteristics of paediatric SS in a United Kingdom (UK) multi-centre cohort of patients. Using this data our goal is to develop universally accepted classification criteria that could be validated for use in a paediatric population.

Inclusion criterion for the study and repository is a diagnosis of SS made before 18 years by the referring physician. A data collection pack will be sent to authors willing to participate. Information collected will include but not exclusive to: demographic, clinical and laboratory/histological data at diagnosis and subsequent follow-up appointments. Biological samples including blood, tears, saliva, urine and glandular and extra-glandular (e.g. renal) tissue will be collected prospectively if available. Outcome measures related to disease activity and damage, as well as patient reported outcomes will also be collected at set time points (every 6 months) and during flares.

PaedSSCoRe will capture data on a significant cohort of children with SS providing a powerful resource to help improve our understanding of the pathogenesis and natural course of this disease.

Prospective data collection will allow a fuller analysis of poor prognostic features, impact of therapy and damage accrual, and variable outcome of childhood SS.

Inclusion Criteria:

1. All recruited patients should be diagnosed with Sjogren's syndrome alone or in association with other autoimmune conditions (rheumatic or not) based on their rheumatologist opinion or have clinical and serological/imaging features which in the opinion of their clinician raise the suspicion of Sjogren's syndrome.
2. Patients with symptoms onset /imaging, serological and glandular biopsy abnormalities suggestive of SS (suspected SS) or SS diagnosis made by expert clinicians prior to age 18
3. Patients/ Carers who can provide informed consent and agree to provide access to the results of their routine care investigations for research purposes irrespective of being able provide blood or saliva samples.
4. Patients of 6 years or age or above

Exclusion Criteria:

1. Inability to provide informed consent or have informed consent provided on their behalf.

Patients with Sjögren's syndrome with childhood-onset Healthy age matched controls Based on our preliminary estimations, there are currently 100-150 JSS patients under hospital care in the UK. The investigators envisaged to capture as many of the patients available, as well as the ones diagnosed for the duration of this project (10 years), estimating a recruitment number limit of 300 patients.

The study will be complying to General Data Protection Regulation (GDPR) and Data protection regulations and personal identifiable information will not be made available to researchers under any circumstances. Data that will be shared will need to be approved by the steering committee in accordance to these regulations.