Ultrastructural analysis of the nuclear envelope in fibroblasts from the subject with HGPS. Low magnification transmission electron microscopic image of a passage 10 PT001 nucleus showed several herniations (a). Two higher-magnification images of the same nucleus at sites of blebs (b and c) showed a close apposition of the chromatin to the nuclear envelope. In a, b, and c the nucleus is to the left. Scale bars correspond to 2 μm in panel a, and 500 nm in panels b and c.