Recessive Severe Usher Syndrome-1 is a genetic disorder characterized by:
Congenital profound sensorineural hearing loss
Retinitis pigmentosa (progressive vision loss due to degeneration of the retina)
Vestibular areflexia (balance problems due to inner ear dysfunction)
It is inherited in an autosomal recessive pattern. Severe forms typically present in infancy or early childhood.
There is evidence that recessive severe Usher syndrome can be caused by mutations in two (2) genes encoded on chromosome #10: CDH23 & PDZD7.
CDH23 (Cadherin 23) & PDZD7 (PDZ domain-containing 7) are critical scaffolding proteins localized to the hair cell stereocilia of the inner ear, both essential for hearing and balance. They are involved in the organization of stereocilia links; CDH23 forms upper tip-links, while PDZD7 is a key component of ankle-links, often interacting with Usher syndrome proteins.
