Subacute combined degeneration of the spinal cord with cystinuria

An 18-year-old man had noticed increasing difficulty in walking for 4 years. Examination disclosed spastic paraparesis and posterior column signs suggestive of subacute combined degeneration of the spinal cord. Urinalysis, urinary thin-layer chromatography, and intestinal biopsy disclosed typical cystinuria. Pernicious anemia and other known enteropathies were excluded. Although this could be a chance association of cystinuria and subacute combined degeneration, one other paper has reported a cystinuria patient with similar neurologic findings. A chance association between cystinuria and nonpernicious anemia subacute combined degeneration of the spinal cord should occur only once in 120 million individuals. Thus, identification of only a few more cases would suggest a pathogenetic link between the two disorders. These observations emphasize the need to search for neurologic signs in patients with cystinuria and to screen the urine of patients with spinal cord signs of obscure origin for cystinuria.