Bardet Biedl Syndrome

Bardet-Biedl Syndrome is a rare inherited condition most commonly found in the Middle East and in island communities like Newfoundland, where the incidence is 1 in 13,500 of the population (supposedly due to higher consanguinity). Elsewhere, the figure is more like 1 in 100,000. The number is rising, as this condition is under-diagnosed.

It is named after Drs. George Bardet and Artur Biedl, who in the 1920s separately observed links between hypothalamic obesity, retinitis pigmentosa, polydactyly, and intellectual impairment.

Characteristic symptoms include:

• atypical retinitis pigmentosa, a progressive eye condition which can lead to blindness,
• obesity (usually with early onset, and resistant to treatment),
• polydactyly (extra fingers and/or toes),
• hypogenitalism (underdeveloped genitals), and
• mild to severe learning difficulties.

To make the diagnosis, four out of five of these features are generally required. In addition, there are other characteristics which should be taken into account:

• kidney dysfunction,
• developmental delay,
• speech difficulties,
• diabetes mellitus or, rarely, diabetes insipidus,
• hepatic fibrosis, and
• hormonal deficiencies.