Incomplete Sjögren-Larsson syndrome in two Japanese siblings

Sjögren-Larsson syndrome (SLS) is a rare, autosomal recessive disorder characterized by ichthyosis, spastic diplegia and mental retardation. Biochemical studies have pinpointed the pathogenesis resulting in the deficiency of the fatty aldehyde dehydrogenase (FALDH) component of the fatty alcohol NAD+ oxidoreductase complex. Histochemical analysis revealed a reduction in alcohol dehydrogenase (AD) activity in the skin. SLS patients have been categorized biochemically into two groups: complete and incomplete reduction according to the degree of FALDH deficiency. Our patients demonstrated incomplete clinical features, including a 1/3 reduction in FALDH activity, and decreased AD activity in the ichthyotic lesion. The phenotypical differences between our cases and classic SLS are probably due to the partial FALDH deficiency.