On the basis of 29 patients aged 1-48 years, the general clinical manifestations and natural course have been determined of a newly described autosomal recessive multisystem condition with carbohydrate-deficient glycoproteins, particularly affecting transferrin. The syndrome showed different presentations during different age periods. During infancy and early childhood failure to thrive, liver dysfunction, pericardial effusions, marked developmental delay and stroke-like episodes were most pronounced. In later childhood and adolescence stationary mental deficiency and ataxia, slowly progressive lower limb neuropathy and pigmentary retinal degeneration, as well as secondary skeletal deformities, were found to be the most disabling constituents. For the purpose of clinical recognition, a four-stage progression based on age is presented.