Diagnosing Bardet-Biedl syndrome (BBS)

A BBS diagnosis is based on four primary features, or it can be based on three primary features and two secondary features.

Primary features:

• Obesity
• Extra fingers/toes (polydactyly)
• Abnormalities of urinary tract
• Learning disabilities
• Rod-cone dystrophy
• Hypogonadism (which may include delayed puberty, genital abnormalities or abnormal endocrine testing of sexual hormones)

Secondary features:

• Speech delay/difficulties
• Strabismus, astigmatism, cataracts
• Short fingers/toes
• Developmental delay
• Excessive thirst/urination
• Awkward gait/imbalance
  
• Spasticity
• Diabetes mellitus
• Dental crowding, high arched palate
• Hepatic fibrosis
• Congenital heart disease