Proteus syndrome: a case with clonal chromosome aberration

Proteus syndrome is a disorder characterized by overgrowth of multiple tissues, connective tissue nevi, epidermal nevi and hyperostoses with asymmetric involvement. The clinical expression of the disorder is extremely variable. Molecular pathogenesis of the syndrome is unknown but it is hypothesized that it resulted from a somatic alteration of a gene leading to mosaic effects that would be lethal if the mutation was carried in nonmosaic fashion, and this may explain the variability among patients. We report a new case who presented at birth with asymmetric hypertrophy of the bones and soft tissues of fingers and a tumor of the chest. Cytogenetic analysis of the excised tumor revealed clonal chromosome aberration: mos46, XY, add(9)(p13) [5]/46,XY[30]. During follow up tumors of the rectum and urinary bladder were diagnosed.