Bardet-Biedl syndrome affects more than one system in the body and symptoms may vary between individuals even in the same family.

Common symptoms that may be seen in this condition include:-

Vision loss

One of the major features of Bardet-Biedl syndrome is loss of vision. Loss of vision occurs as the retina, that is the light sensing tissue or layer at the back of the eye, fails gradually.

The problems appear initially as difficulty in seeing in the dark. This is seen in childhood as a slow onset condition.

This is followed by development of blind spots in vision that leads to falls and knocks initially. Over time, these blind spots enlarge and turn into a tunnel where only the center is visible.

With time the central clear area also clouds. By the time the child reaches adolescence or early adulthood, he may become legally blind.

Obesity

Another characteristic feature is obesity. There is typical abdominal obesity that begins in early childhood and continues throughout life.

Obesity related conditions

Obesity may give rise to other complications like type 2 diabetes, high blood pressure and abnormally high levels of cholesterol.

Abnormalities of the fingers and/or toes

Typically there may also be presence of extra fingers and/or toes. In addition the fingers and/or toes may be short and fused together.

Learning difficulties

There may be mental retardation, learning problems, intellectual disability and impaired speech. There may be delayed development of motor skills such as standing and walking.

Behavioral problems

There are associated behavioral problems including emotional immaturity and inappropriate outbursts, and clumsiness or poor coordination.

Underdeveloped genitals

The genital organs may also be underdeveloped. The amount of sex hormones produced by males with this condition is typically low and this makes them infertile.

Kidney and other organ problems

There may be mild to severe life threatening kidney problems and kidney formation abnormalities in these patients. The heart, liver, and digestive system may also be affected. In the heart there may be enlargement of the ventricles and cardiomyopathy. In the digestive system there may be presence of fibrosis.

Facial abnormalities

There are distinctive facial abnormalities in most patients. There are jaw and tooth deformities. There may be extra teeth or small and thin teeth roots.

Due to these deformities snoring is common. In addition there may be feeding difficulties and drooling as well.

Anosmia

There may be a partial or complete loss of the sense of smell (anosmia).