X-linked Sideroblastic Anemia and Ataxia

Several forms of congenital or progressive ataxia have an X-linked pattern of inheritance. The gene for one form of progressive ataxia, X-linked sideroblastic anemia and ataxia (XLSA/A) has been identified (Table 2). XLSA/A is an infantile-onset gait disorder affecting male children beginning with delayed motor milestones and followed by onset of slowly progressive ataxia between 40 and 50 years of age. The disorder may lead to confinement to wheelchair after at least 10 years of disease progression. Examination of adults shows dysarthria, ataxia of upper limbs and gait, ophthalmoparesis, hypometric saccades, saccadic pursuit, nystagmus, occasional perioral fasciculations, normal to increased deep tendon reflexes and normal plantar reflexes, sensory examination and negative Rhomberg sign. The gene responsible for XLSA/A is located on Xq13 and encodes the human ATP-binding cassette (ABC) transporter ABC7.