Summary: Background: Bardet‐Biedl syndrome (BBS) is a rare genetic disorder that severely inhibits primary cilia function. BBS is typified by obesity in adulthood, but pediatric weight patterns, and thus optimal periods of intervention, are poorly understood.Objectives: To examine body mass differences by age, gender, and genotype in children and adolescents with BBS.Methods: We utilized the largest international registry of BBS phenotypes. Anthropometric and genetic data were obtained from medical records or participant/family interviews. Participants were stratified by age and sex categories. Genotype and obesity phenotype were investigated in a subset of participants with available data.Results: Height and weight measurements were available for 552 unique individuals with BBS. The majority of birth weights were in the normal range, but rates of overweight or obesity rapidly increased in early childhood, exceeding 90% after age 5. Weight z‐scores in groups >2 years were above 2.0, while height z‐scores approached 1.0, but were close to 0.0 in adolescents. Relative to those with the BBS10 genotype, the BBS1 cohort had a lower BMI z‐score in the 2‐5 and 6‐11 age groups, with similar BMI z‐scores thereafter. Children with biallelic loss of function (LOF) genetic variants had significantly higher BMI z‐scores compared to missense variants.Conclusion: Despite normal birth weight, most individuals with BBS experience rapid weight gain in early childhood, with high rates of overweight/obesity sustained through adolescence. Children with LOF variants are disproportionally affected. Our findings support the need for earlier recognition and initiation of weight management therapies in BBS.

Time spent among the 24-h movement behaviors (physical activity [PA], sleep, sedentary behavior [SB]) in the perinatal period is important for maternal and child health. We described changes to 24-h movement behaviors and behavior guideline attainment during pregnancy and postpartum and identified correlates of behavior changes. This secondary data analysis included the standard of care group (n = 439) from the U.S.-based Lifestyle Interventions For Expectant Moms (LIFE-Moms) consortium, including persons with overweight and obesity. Wrist-worn accelerometry was used to measure movement behaviors early (9–15 weeks) and late (35–36 weeks) pregnancy, and ∼ 1-year postpartum. Sleep and moderate-to-vigorous PA (MVPA) were compared to adult and pregnancy-specific guidelines, respectively. SB was classified into quartiles. PA and SB context were quantified using questionnaires. Mixed models were used to examine changes in behaviors and guidelines and identify correlates. Participants were 31.3 ± 3.5 years, 53.5 % were Black or Hispanic, and 45.1 % had overweight. Sleep duration decreased across time, but participants consistently met the guideline (range: 85.0–93.6 %). SB increased during pregnancy and decreased postpartum, while light PA and MVPA followed the inverse pattern. Participants met slightly fewer guidelines late pregnancy (1.2 ± 0.7 guidelines) but more postpartum (1.7 ± 0.8 guidelines) than early pregnancy (1.4 ± 0.8 guidelines). Black or Hispanic race/ethnicity, higher pregravid body mass index, and non-day work-shift (e.g., night-shift) were identified correlates of lower guideline adherence and varying PA and SB context. Perinatal interventions should consider strategies to prevent SB increase and sustain MVPA to promote guideline adherence.

Purpose of review: Bardet Biedl syndrome (BBS) is a rare disease characterized by obesity and hyperphagia. Despite the very high prevalence of paediatric and adult obesity in this population, the prevalence of diabetes mellitus is not well described. Recent findings: Studies in small and moderately large cohorts suggest a high prevalence of traditional risk factors for diabetes mellitus in people with BBS. People with BBS appear to have a high prevalence of insulin resistance and metabolic syndrome. Small cohort studies have identified high rates of sleep disordered breathing, including sleep apnoea syndrome. Recent research has characterized traditional behavioural risk factors such as sleep hygiene and physical inactivity in people with BBS. High rates of insufficient sleep and prolonged sedentary time suggest behavioural targets of interventions to treat or prevent diabetes mellitus. Hyperphagia, likely caused by defects in the hypothalamic melanocortin-4 receptor (MC4R) neuronal pathway, pose additional challenges to behavioural interventions to prevent diabetes mellitus. Summary: Understanding the prevalence of diabetes mellitus and other metabolic disorders in people with BBS and the impact of traditional risk factors on glucose regulation are important to developing effective treatments in this population.

Background: Overweight and obesity are common features of the rare disease Bardet–Biedl syndrome (BBS). Sleep and physical activity are behaviors that might impact overweight and obesity and thus may play a key role in the health and well-being of people with BBS. Objectively-measured sleep and physical activity patterns in people with BBS are not well known. We evaluated objectively-measured sleep and physical activity patterns in the largest cohort to date of people with BBS. Results: Short sleep duration, assessed using wrist-worn accelerometers, was common in both children and adults with BBS. Only 7 (10%) of adults and 6 (8%) of children met age-specific sleep duration recommendations. Most adults 64 (90%) achieved recommended sleep efficiency. The majority of children 26 (67%) age 6–12 years achieved recommended sleep efficiency, but among children age 13–18, only 18 (47%). In both adults and children, sleep duration was significantly negatively correlated with duration of prolonged sedentary time. In children age 6–12 sleep duration was also significantly related to total activity score, children with lower sleep duration had lower total activity scores. Conclusions: Insufficient sleep duration is very common in people with BBS. Prolonged sedentary time and short sleep duration are both potentially important health-related behaviors to target for intervention in people with BBS.