Bardet-Biedl Syndrome in Children Shows Obesity but Milder Hormonal Deficits Than Adults
A 135-patient pediatric study finds obesity and short stature dominate BBS, while hypogonadism and hypothyroidism remain rare in childhood.
Summary
Bardet-Biedl syndrome (BBS) is a rare genetic disorder affecting multiple organ systems, including the endocrine system. This large single-center study of 135 children with confirmed BBS found that obesity and short stature are the dominant endocrine features in childhood. Surprisingly, hypogonadism — a hallmark of adult BBS — was absent in this pediatric cohort, and hypothyroidism was rare. Over three-quarters of older children had obesity, and more than half had elevated triglycerides, signaling early metabolic risk. Diabetes and impaired glucose tolerance were uncommon but present. These findings suggest that the full endocrine burden of BBS may emerge gradually with age, making early metabolic monitoring and longitudinal follow-up critical for this population.
Detailed Summary
Bardet-Biedl syndrome is a rare inherited ciliopathy — a disorder of the tiny hair-like structures that regulate cellular signaling — affecting roughly 1 in 140,000 people. It is classically associated with obesity, vision loss, extra fingers or toes, kidney abnormalities, cognitive impairment, and hormonal dysfunction. While adult patients often develop hypogonadism and hypothyroidism, the endocrine profile in children has been poorly characterized until now.
Researchers at Great Ormond Street Hospital conducted a retrospective analysis of 135 pediatric patients with genetically confirmed BBS, ranging in age from 1.2 to 19.4 years. This represents the largest pediatric endocrine dataset for BBS to date. Data on height, BMI, thyroid function, reproductive hormones, glucose metabolism, and lipids were extracted from electronic medical records.
Obesity was the most striking finding: 77.6% of patients aged 15 and older met criteria for obesity, and BMI worsened progressively over time. Short stature affected 21.1% of older patients. Elevated triglycerides were present in 55.5% of the cohort, indicating widespread dyslipidemia even in childhood. Diabetes (type 1 and type 2 combined) and impaired glucose tolerance each affected small but meaningful proportions of patients.
In contrast, hypogonadism — a defining feature of adult BBS — was entirely absent in this pediatric group. No child required pubertal induction or hormone replacement. Hypothyroidism was identified in fewer than 3% of patients, far below rates reported in adults with BBS.
These findings suggest that endocrine complications in BBS follow a developmental trajectory, with metabolic dysfunction emerging early and reproductive and thyroid dysfunction developing later. Clinicians managing children with BBS should prioritize obesity and lipid monitoring from an early age. Longitudinal studies bridging pediatric and adult care are needed to map the full natural history of this condition.
Key Findings
- 77.6% of BBS patients aged 15+ had obesity, with BMI worsening progressively over time.
- Elevated triglycerides were found in 55.5% of children, signaling early cardiovascular metabolic risk.
- Hypogonadism was absent in all 135 pediatric patients, unlike adult BBS populations.
- Short stature affected 21.1% of older children, confirming it as a core pediatric feature.
- Hypothyroidism was rare (under 3%), suggesting it emerges later in the disease course.
Methodology
This was a retrospective analysis of prospectively collected data from 135 genetically confirmed pediatric BBS patients at a single multidisciplinary center (Great Ormond Street Hospital). Height Z-scores, BMI trajectories, thyroid function, reproductive hormones, glucose tolerance, and lipid panels were extracted from electronic records. Short stature was defined as height Z-score below -2 or more than 1.6 SDS below mid-parental height.
Study Limitations
This summary is based on the abstract only, as the full text is not open access. The single-center design at a specialist referral hospital may limit generalizability to broader BBS populations. The retrospective nature and variable follow-up duration may introduce ascertainment bias in endocrine outcome reporting.
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