ESPE Abstracts

Introduction: Bardet-Biedl syndrome (BBS) is a rare, pleiotropic, autosomal recessive disorder, with prevalence between 1 in 100,000 – 160,000 in Europe and the USA. It is characterised by 6 cardinal features: rod-cone dystrophy, truncal obesity, cognitive impairment, hypogonadism and genitourinary anomalies, postaxial polydactyly and renal dysfunction, as well as a plethora of secondary features spanning multiple body systems. BBS belongs to a family of inherited ciliopathies, which manifest secondary to genetically acquired anomalies in the proteins responsible for the maintenance of primary ciliary integrity - these result from mutations in a constellation of at least 21 identified genes, referred to as BBS genes. Hypogonadism is one of the hallmarks of BBS. Historically patients have been thought to present with absent or delayed puberty, resulting in close monitoring of pubertal development, and the use of hormone replacement therapy (HRT) to induce and maintain pubertal progression in some cases.

Objective: To review historical cases to ascertain whether children with BBS spontaneously entered and progressed through puberty normally, without the use of HRT.

Method: A retrospective 10-year review was conducted of paediatric patients diagnosed with BBS and managed in a specialist tertiary/quaternary UK Centre. The cohort of BBS patients was retrieved from a secure database, managed and developed by Certus Technology Associates. Data was also collected from Electronic Patient Records.

Results: 113 patients diagnosed with BBS presented to our Centre from 2010 - 2019; 68 were male. Their age at presentation was between 1.1 and 18 years (median 9.4 years). Three male patients had received testosterone treatment briefly during childhood and all later spontaneously entered puberty. No female patients have received HRT to date. All patients in this cohort entered puberty spontaneously; only 1 male had delayed puberty, with onset at the age of 15.4 years. Delayed puberty was not seen in any of the females. Of this cohort 27% have completed puberty to date.

Conclusion: Although the literature states that patients with BBS are at risk of delayed puberty and likely to require pubertal induction, our data shows that 99% of our studied cohort entered puberty spontaneously, without delay. Ongoing follow up and surveillance are needed to ensure that there is no evidence of pubertal arrest and to ascertain HRT requirements in adulthood. Further data regarding fertility outcomes are also needed.