The goal of this observational study is to learn about the long-term effects of GLP1 agonists (weight loss jab, including Mounjaro) in patients with Bardet-Biedl Syndrome (BBS) who take GLP1 agonists to treat high body weight. The main question:

Do GLP1 agonists effectively and safely lower body weight in patients with BBS when taken long-term, compared to patients not on these medications? The investigators look at the change (%) in weight during the observational periods.

Demographics on time zero: Age, gender, Race, Body Weight (BW), Body Mass Index (BMI), Blood Pressure (clinic, DM meds), Pulse, Lipid profiles (Chol, HDL, LDL, TG), eGFR, HBA1c, (if feasible) genetic diagnosis

Primary outcome at the end of study date : Body weight change (%)

Secondary outcome at the end of study date: change in lipid (Chol, HDL, LDL, TG), Blood Pressure, DM status

Quality assurance plan: data validation will be secured due to the electronic record. The registry process was undertaken in our closed national BBS centres quality assured by multi-disciplinary team (MDT) looked after by senior specialty nurses, who followed all the patients with GLP1 agonists monthly over the telephone.

Data checks to compare data entered into the registry against predefined rules for range or consistency with other data fields in the registry.

Source data verification to assess the accuracy, completeness, or representativeness of registry data by comparing the data to external data sources.

Plan for missing data to address situations where variables are reported as missing, unavailable, non-reported, uninterpretable, or considered missing because of data inconsistency or out-of-range results: The investigators followed all the missing data by contacting patients' family doctors (GP) and their records.

Statistical analysis plan describing the analytical principles and statistical techniques to be employed in order to address the primary and secondary objectives, as specified in the study protocol or plan.

Inclusion Criteria:

• All the adult patients with a genetic diagnosis of BBS under the national BBS centres (London and Birmingham in the UK).

Exclusion Criteria:

• Adult patients with a genetic diagnosis of BBS under the national BBS centres (London and Birmingham in the UK) who lost follow ups or significant missing data, or BMI<30 in patients without GLP1 agonists.

All the patients with a genetic diagnosis of BBS living in the UK under the UK National BBS Centres (Birmingham and London).

The study protocol, Age, gender, Race, BW, BMI, BP and pulse (clinic), diabetic medications, Lipid (Chol, HDL, LDL, TG), eGFR, HBA1c, genetic diagnosis

Beginning right after publication with no end date

a data sharing agreement must be signed, and those documents can be submitted via emails.