The Endocrine and Metabolic Characteristics of a large Bardet-Biedl syndrome clinic population.
Mujahid S., Hunt KF., Cheah YS., Forsythe E., Hazlehurst JM., Sparks K., Mohammed S., Tomlinson JW., Amiel SA., Carroll PV., Beales PL., Huda MSB., McGowan BM.
Context: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder in which previous reports have described obesity and a metabolic syndrome. Objective: Describe the endocrine and metabolic characteristics of a large BBS population compared with matched controls. Design: Case-control. Setting: Hospital clinic. Patients: A clinical/genetic diagnosis of BBS. Intervention: None. Main outcome measure: Prevalence of metabolic syndrome. Results: One hundred and fifty-two subjects were studied. Eight-four (55.3%) were male and mean (±SD) age was 33.2±1.0 years. Compared with age, gender and BMI matched controls, fasting glucose and insulin levels were significantly higher in BBS subjects (glucose: BBS: 5.2±1.2mmol/l vs control 4.9±0.9mmol/l, p=0.04; insulin: BBS: 24.2±17.0pmol/l vs control 14.2±14.8pmol/l, p<0.001). Serum triglycerides were significantly higher in BBS subjects (2.0±1.2mmol/l) compared with controls (1.3± 0.8mmol/l p<0.001) but total cholesterol/HDL/LDL were similar in both groups. Systolic blood pressure was higher in the BBS group (BBS 135±18 mmHg vs controls 129±16mmHg (p=0.02). Alanine transaminase (ALT) was raised in 34 (26.8%) BBS subjects, compared to 5 (8.9%) controls (p=0.01). The presence of a metabolic syndrome, using IDF criteria, was significantly higher in the BBS group (54.3%) compared to controls (26% p<0.001). Twenty-six (19.5%) of BBS males were hypogonadal (serum testosterone 9.9±5.3 mmol/l) but significant pituitary abnormalities were uncommon. Subclinical hypothyroidism was present in 24/125 (19.4%) patients with BBS compared with 3/65 (4.6%) controls (p=0.01). Conclusions: Insulin resistance and the metabolic syndrome are increased in adult BBS compared with matched controls. Increased subclinical hypothyroidism in the BBS cohort is a novel finding that needs further investigation.