The Bardet–Biedl syndrome is a ciliopathic human genetic disorder that produces many effects and affects many body systems. It is characterized principally by obesity, retinitis pigmentosa, polydactyly, mental retardation, hypogonadism, and renal failure in some cases.
The syndrome is named after Georges Bardet and Arthur Biedl. 14 genetic forms have been currently identified.
The first known case was reported by Laurence and Moon in 1866 at the Ophthalmic Hospital in South London. Laurence–Moon–Biedl–Bardet syndrome are no longer considered as valid terms in that patients of Laurence and Moon had paraplegia but no polydactyly and obesity, which are the key elements of the Bardet–Biedl the syndrome. Laurence–Moon syndrome is usually considered a separate entity. However, some recent research suggests that the two conditions may not be distinct.
Bardet–Biedl syndrome is a pleiotropic disorder with variable expressivity and a wide range of clinical variability observed both within and between families.
The main clinical features are rod–cone dystrophy, with childhood-onset visual loss preceded by night blindness; postaxial polydactyly; truncal obesity that manifests during infancy and remains problematic throughout adulthood; specific learning difficulties; male hypogenitalism and complex female genitourinary malformations; and renal dysfunction, a major cause of morbidity and mortality.
There is a wide range of secondary features that are sometimes associated with BBS including;
- Speech disorder/delay
- Strabismus/cataracts/astigmatism
- "Brachydactyly/syndactyly of both the hands and feet is common, as is partial syndactyl (most usually between the second and third toes)"
- "Developmental delay: Many children with BBS are delayed in reaching major developmental milestones including gross motor skills, fine motor skills, and psychosocial skills (interactive play/ability to recognize social cues)"
- Polyuria/polydipsia (nephrogenic diabetes insipidus)
- Ataxia/poor coordination/imbalance
- Mild hypertonia (especially lower limbs)
- Diabetes mellitus
- Dental crowding/hypodontia/small dental roots; high-arched palate
- Cardiovascular anomalies
- Hepatic involvement
- Anosmia
- Auditory deficiencies
- Hirschsprung disease
Further Reading
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