
Townes-Brocks and Okihiro Syndrome
Townes-Brocks syndrome is a rare genetic disease caused by a mutation of the SALL1 gene, resulting in malformations of the fingers and/or toes. However, also abnormalities of the kidneys and heart have been reported. Some children with this genetic disorder also show learning difficulties, and in severe cases mental retardation.
The Okihiro syndrome, also known as Duane-radial ray syndrome, is a rare disorder caused by mutation the SALL4 gene. Besides bone abnormalities in hands and feet, such as an extra or absent thumb, this condition is often accompanied by the so-called Duane anomaly, in which the proper movement of the eye is impaired resulting in a limitation of out- or inward eye movement.