Endocrine Abstracts

Introduction: Bardet-Biedl Syndrome is a rare autosomal recessive disease characterized by defects in multiple organ systems, presenting with diverse clinical manifestations such as retinopathy, polydactyly, obesity, intellectual developmental disorders, hypogonadism, renal dysfunction, among others.

Clinical Case 1: 49-years-old female, case index, followed multidisciplinary since the age of three due to progressive night blindness from generalized retinal dystrophy, learning difficulties, primary amenorrhea and polycystic ovary syndrome, epilepsy, metabolic syndrome (grade 2 obesity, grade 1 hypertension, dyslipidemia), chronic kidney disease and musculoskeletal alterations (macrocephaly, short stature, and scoliosis). It is worth highlighting parental consanguinity. Given the phenotype clinically suggestive of Bardet-Biedl Syndrome, a whole exome sequencing was performed revealing the genetic variant c.1542del p.(Asp515IIefs*9), in apparent homozygosity, of the BBS10 gene, classified as likely pathogenic, confirming the diagnosis.

Clinical Case 2: 45-years-old male, brother of case index, followed since childhood for retinal dystrophy with progressive bilateral night blindness, intellectual developmental disorder, metabolic syndrome (grade 3 obesity, dyslipidemia, type 2 diabetes under insulinotherapy), chronic kidney disease, moderate unilateral sensorineural deafness requiring hearing aid and musculoskeletal alterations (scoliosis and macrocephaly). As in the index case, the patient was advised in a medical genetics’ consultation and the same genetic variant was identified, confirming the genetic diagnosis of Bardet-Biedl Syndrome.

Clinical Case 3: 36-years-old male patient, first cousin of the above-mentioned individuals, also followed since childhood for bilateral retinal dystrophy, intellectual developmental disorder, cryptorchidism treated with orchidopexy in childhood, grade 1 obesity and arterial hypertension. Additionally, post-axial bilateral polydactyly in the feet. Given the similar phenotype, genetics consultation was performed and the same genetic variant was identified in homozygosity. Genetic counseling for the family was provided.

Conclusion: This report presents three cases of Bardet-Biedl Syndrome within a family, detailing the associated diagnosis process, emphasizing the role of identifying a clinical phenotype and guiding genetic studies. The cases underscore the importance of early recognition of characteristic phenotypes where obesity is a key element, often overlooked, limiting proper patient management.