CTNNB1 syndrome is a genetic disorder resulting from a disease-causing change in the sequence of CTNNB1 gene, located on chromosome 3.

Affected individuals may present to medical attention for development delay, intellectual disability, low muscle tone in the trunk and altered tone in the arms and legs. They may have involuntary muscle contractions leading to an abnormal posture and repetitive movements. They are often found to have a small head and may have various forms of eye conditions. However, the severity and presentation is highly variable amongst affected individuals and some may present with visual problem only. In particular, the CTNNB1 syndrome was found to be associated with a rare eye condition called familial exudative vitreoretinopathy (FEVR) which affects the blood vessels at the back of the eye (retina) and may cause blindness in some.

This is a rare condition and the exact number of cases in the population remains unknown.

For additional information, please see:
CTNNB1 syndrome –Rarechromo.org