SNP Shot: Genomic Insights

Bardet-Biedl syndrome (BBS) is a multi-system disorder, meaning it affects numerous parts of the body. The signs and symptoms associated with BBS can vary significantly, even among individuals within the same family.

A primary characteristic of BBS is vision impairment. This impairment arises from the gradual degeneration of the retina, the light-sensitive tissue at the back of the eye. Typically, difficulties with night vision become noticeable during mid-childhood, followed by the appearance of blind spots in peripheral vision. As the condition progresses, these blind spots expand and merge, leading to tunnel vision. Furthermore, many individuals with BBS experience blurred central vision (reduced visual acuity) and are classified as legally blind by adolescence or early adulthood.

Obesity is another significant feature of Bardet-Biedl syndrome. Excessive weight gain usually starts in early childhood and remains a persistent issue throughout the person's life. Obesity-related complications can include type 2 diabetes, hypertension (high blood pressure), and hypercholesterolemia (abnormally high cholesterol levels).

Other major signs and symptoms associated with BBS involve polydactyly (extra fingers or toes), intellectual disability or learning difficulties, and genital abnormalities. Hypogonadism, characterized by reduced production of sex hormones, is common in affected males, often resulting in infertility. Kidney abnormalities are also frequently observed in individuals with Bardet-Biedl syndrome and can range from mild to life-threatening.

Other potential features of BBS encompass speech impairments, delayed motor skill development (e.g., standing and walking), behavioral problems (such as emotional immaturity and inappropriate outbursts), and poor coordination. Specific facial features, dental problems, unusually short or fused digits (fingers or toes), and anosmia (loss of the sense of smell) have also been reported in some individuals. Additionally, the condition can affect the heart, liver, and digestive system.

Inheritance:

Bardet-Biedl syndrome is usually inherited in an autosomal recessive manner. This means that a mutation must be present in both copies of a BBS gene in each cell for the condition to develop. Individuals with only one copy of the mutated gene are carriers; they typically do not exhibit any signs or symptoms of the syndrome but can pass the mutated gene to their children.