Figure 2

Recessive mutation in FBN2 in family 16DG0107. (a) and (b) Representative images of the widespread striae. (c) The muscle biopsy results show myopathic features with variation in fiber size and scattered atrophic fibers (arrow, hematoxylin and eosin, ×400). (d) Ultrastructural examination shows scattered foci of myofibrillar disruption (arrow, EM ×4,000). (e) Rodlike structures are noted occasionally at the periphery of some fibers, within a background of myofibrillar disarray (EM ×25,000). (f) Computational 3D models of FBN2 residues 1–28 (which constitute the signal peptide) for the wild-type Leu14 (left) and mutant Arg14 (right). Position 14 is encircled. Orientation is with the N-terminal upward. Top panels: ribbon representation. Bottom panels: electrostatic surface, color-ramped from blue (basic/positively charged) to gray (uncharged/hydrophobic) to red (acidic/negatively charged). The theoretical 3D model has been established based on a helical secondary structure prediction for residues 2–28 and weak homology to PDB id 5i6c (P value = 3.7 × 10⁻²).