CEREBRAL ADRENOLEUKODYSTROPHY (ALD) IN ONLY ONE OF MONOZYGOTIC TWINS WITH AN IDENTICAL ALD GENOTYPE

We report on monozygotic twins with different clinical phenotypes of X -linked adrenoleukodystrophy. At the age of 10 years both boys were ne urologically asymptomatic. The first cranial magnetic resonance examin ation showed normal findings in the first twin and parietooccipital de myelination in the second. The latter developed behavioral problems 9 months later, followed by visual impairment and gait ataxia. His crani al magnetic resonance image at the age of 11 years showed progressive demyelination. In contrast, neurological status and magnetic resonance images remained normal in the first twin. The same point mutation in exon 8 of the adrenoleukodystrophy gene (C2203T) was detected in both boys. All genotype examinations were consistent with the diagnosis of monozygotic twins, suggesting that some nongenetic factors may be impo rtant for different adrenoleukodystrophy phenotypes.