Hyperleucine-isoleucinemia.
Incidence
Autosomal recessive. Very rare disease.
Clinical Characteristics
The only description of a leucine-isoleucine abnormality was provided by Jeune et al. (1970) in a French family. A brother and sister presented at ages 2 to 3 months with seizures, failure to thrive, and mental retardation. The girl had retinal degeneration and sensorineural hearing loss as well. Blood analysis showed elevated concentrations of leucine, isoleucine, and proline with normal levels of valine. Aminotransferase activity in the leukocytes of these 2 patients showed decreased transfer from leucine and isoleucine but normal activity with valine (There are 2 branched-chain amino acid transferases, BCT1 and BCT2. There is evidence, furthermore, that the transamination of valine may be separate from the transamination of leucine and isoleucine). Treatment with diets low in leucine and isoleucine did not improve the clinical phenotype and the boy died in his third year.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
EB-W. Decreased leucine and isoleucine aminotransferase. Normal valine aminotransferase. Aminoacids in plasma, quantitative.