Sjögren-Larsson syndrome (SLS) is a rare autosomal recessively inherited neurocutaneous disorder caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase, an enzyme that catalyzes the oxidation of fatty aldehyde to fatty acid. It is characterized by an unusual combination of cutaneous and neurologic signs and symptoms. The authors describe two brothers of consanguineous parents with SLS, one of whom was born from a dizygotic twin pregnancy (with an apparently normal sister), and they focus on the variability of the clinical findings of the syndrome even among siblings and twins.