Usher syndrome in four siblings from a consanguineous family of Pakistani origin.

Usher syndrome is a heterogeneous group of disorders of autosomal recessive inheritance characterized by retinitis pigmentosa and congenital sensorineural hearing loss. Two types are accepted clinically: type I is associated with profound congenital deafness with progressive pigmentary retinopathy and total loss of vestibular function. Type II is a milder form, with moderate-to-profound hearing loss and a milder form of retinitis pigmentosa. Vestibular function is preserved. A total of five loci have been identified as accounting for the two distinct phenotypic presentations. We describe a consanguineous family of Pakistani origin whose four children all are affected with Usher syndrome type I. DNA analysis showed non-linkage to any of the loci already identified as tightly linked to the Usher syndrome type I.