Bardet-Biedl Syndrome (ARL6)
Bardet-Biedl syndrome (ARL6-related) is an autosomal recessive disorder caused by pathogenic variants in the gene ARL6. Symptoms include rod-cone dystrophy (an eye disorder affecting the light sensitive cells of the retina), truncal obesity, postaxial polydactyly, cognitive impairment, male hypogonadotropic hypogonadism, complex female genitourinary malformations, and renal abnormalities. Individuals experience night blindness by childhood and are diagnosed with legal blindness by an average age of 15 years. While most patients are expected to survive into adulthood, earlier death may occur when renal disease is severe. This disorder is most prevalent in European populations and among the Bedouin of the Kuwait population. Variants in ARL6 may also cause isolated retinitis pigmentosa. The onset of this condition ranges from childhood to adulthood. It typically begins with the onset of night blindness that progresses to tunnel vision and blindness. No clear genotype-phenotype correlation has been established.
For information about carrier frequency and residual risk, please see the residual risk table.