Endocrine Abstracts

Background: Bardet–Biedl syndrome is a rare multisystem autosomal recessive disorder that falls under the spectrum of ciliopathy disorders. This ciliopathy is characterized by rod–cone dystrophy, renal malformations, polydactyly, learning difficulties, central obesity, and hypogonadism [1]. It was first described by Bardet [2] in 1920 and then by Biedl [3] in 1922. Its prevalence in Europe and North America is 1:100 000 [4]. The incidence of this syndrome is higher in the Faroe Islands and Kuwait, with 1:3700 and 1:17 000 live births, respectively [5]. According to the diagnostic criteria published by Beales et al., the diagnosis of BBS is based on the presence of at least four primary features or three primary features and at least two secondary features [2]. The management of BBS is supportive through a multidisciplinary team approach.

Case presentation: A 50-year-old single man presented to a university hospital, complaining of easy fatigue. The patient began to develop night blindness at the age of 7 years, and by the age of 15, he had entirely lost his vision. He had been diagnosed with diabetes mellitus for the preceding 6 years, and he had been managing it with insulin therapy and was experiencing frequent attacks of hypoglycemia. There is a history of polydactyly and visual impairment in the family. On physical examination, the patient was pale. He was 175 cm tall and 96 kg heavy, with a BMI of 31.3 kg/m², indicating obesity. His vital signs were normal. Fundus examination showed features of retinitis pigmentosa. Examination of the extremities showed post-axial polydactyly in both the upper and lower limbs. Laboratory investigations showed normochromic normocytic anemia, features of subclinical hypothyroidism, and a high renal profile. Abdominal ultrasonography revealed bilateral small kidney size, and echocardiography showed left ventricular hypertrophy. The diagnosis of BBS was made on the basis of the presence of four items of primary features (obesity, retinitis pigmentosa, post-axial polydactyly, and renal abnormalities) in addition to two secondary features (diabetes mellitus and left ventricular hypertrophy).

Conclusion: BBS is a rare clinical syndrome that may go unnoticed by many clinicians. Increased awareness among physicians is required for the early diagnosis and treatment of Bardet–Biedl syndrome and to avoid complications and mortality. The combined presence of post-axial polydactyly, blindness, learning disabilities, renal malformations, and obesity in a diabetic patient should alert to the possibility of BBS.