Ataxia-Deafness-Retardation Syndrome is a rare genetic syndrome characterized by intellectual disability, deafness, ataxia, developmental delay and progressive sensorineural hearing loss. It is different from the Richards-Rundle syndrome, although both share the ataxia, deafness, and intellectual disability. The condition shows an autosomal recessive pattern of inheritance. However, one of the studies has also suggested X-linked inheritance as a possible inheritance pattern.
Reardon et al. (1993) reported two brothers with Ataxia-Deafness-Retardation Syndrome in a consanguineous family from Kuwait. The brothers, who were born at term to first-cousin parents, showed slight delays in attaining their developmental milestones. Both had unsteady gaits with signs of cerebellar incoordination, in addition to a severe bilateral sensorineural hearing loss. The younger brother suffered a few episodes of febrile seizures. There were no dysmorphic or neurocutaneous features, and no evidence of muscle wasting. By 7-years of age, both patients had an ataxic gait, reduced tone in the upper limbs, and global developmental delay. The family pedigree showed a similarly affected maternal male first cousin, also born to consanguineous parents. Reardon et al. (1993) speculated that both autosomal recessive and X-linked inheritance could be a possibility in this family.