Novel SPG3A and SPG4 mutations in two patients with Silver syndrome.

Hereditary spastic paraplegia encompasses a group of disorders that are characterized by progressive lower extremity weakness and spasticity. We describe two patients with Silver phenotype including one with a novel SPG4 (Spastin) mutation and a second with a known SPG 4 mutation (previously unassociated with this phenotype) and a concomitant previously unreported mutation in SPG3A (Atlastin). These cases suggest that Silver syndrome may be associated with a wider variety of genotypes than previously described.