Bardet-Biedl Syndrome

Main Features

  • Dysfunction of Brain, eye, kidneys and genitalia

Eye Findings

  • Retinal degeneration (almost 100%)
    • Rod-cone dystrophy with early macular involvement
      • Pigmentary changes in macula first
      • ERG
    • Symptoms in order of presentation
      • Nyctalopia age 4-8 years
      • Progressive peripheral vision loss
      • Decline of color vision
      • Legal blindness by 20-30 years old
  • Strabismus
  • Cataracts
  • Astigmatism
Bardet-Biedl Syndrome Retinopathy Clinical Grading System
Grade Description Subtypes Clinical Features
0 Normal None
1 Preclinical Retinopathy No fundoscopic evidence of retinopathy but evidence of reduced visual function (acuity, visual fields, ERG)
2 Clinical Retinopathy 2c Central disease with foveal atrophy
2p Peripheral disease with pigmentary reinopathy
2g Global disease with central and peripheral involvement but no features of stage 3
3 End-stage retinopathy Advanced central and peripheral involvement, which may include extensive scarring, vascular attenuation, choroidal atrophy, and significant disc pallor

Adapted from Dennison AK et al. Retina 2014;34:2282-2289

Other Findings

  • Obesity
  • Postaxial polydactyly
  • Renal anomalies
  • Learning disability
  • Hypogonadism and Genitourinary abnormalities
  • Cardiac defects

From resource 1 below

Etiology

  • Non-motile ciliopathy- dysfunction of the primary cilium.
  • Autosomal Recessive

Resources

  1. Bardet-Biedl Syndrome: Current Perspectives and Clinical Outlook. Melluso A et al. Therapeutics and Clinical Risk Management. 2023;19:115-132
  2. Evaluation of Visual Function and Needs in Adult Patients with Bardet-Biedl Syndrome. Denniston AK et al. Retina 2014;34:2282-2289