Figure 1.
Pedigree structure and characteristic of the MO proband.
(a) Pedigree structure of the MO family; (b,c) computed radiography and 3D reconstruction images of knees of the MO proband. The proband exhibits multiple exostoses, arising from the lateral ends of femurs, tibiae and fibulae. Arrowhead denotes the chondroma used for histochemistry staining; (d–f) low-power micrograph (4×) of the proband’s chondroma sections stained by hematoxylin-eosin (d), Safranin O (e) and Toluidine Blue (f). The cartilage cap of MO is covered by fibrous perichondrium and merges into the underlying spongy bone.
Figure 2.
Identification of a frameshift mutation in codon 486 of EXT1 gene.
(a) Sanger sequencing detected the inserted base in the EXT1 gene of all affected subjects. Red arrowhead denotes the mutation position; (b) intron-exon structure of EXT1 gene. Mutated exon is indicated by red arrowhead; (c) comparison of the functional domains of EXT1 proteins encoded by mutated and normal EXT1 genes; (d) multiple sequence alignment of codon 485 to codon 487. Codon 486 is highly conserved across various vertebrates.
Figure 3.
Immunohistochemisty screening of chondrocytes with functional EXT1 in the superficial layers of cartilage caps of MO(a) and extragenetic solitary chondroma(b) (40×).
The chondrocytes with functional EXT1 in MO are less than those in extragenetic solitary chondroma.
Table 1.
Characteristics of study subjects in MO family.