Homeobox transcription factors (Hox proteins), play important roles in specifying whether a particular mesenchymal cell will become stylopod. zeugopod or autopod, Based on the expression patterns of these genes, a model was proposed wherein these Hox genes specify the identity of a limb region. What would be the observed phenotype for human homozygous for a HOXD13 mutation?
1
No zeugopod formation.
2
Abnormalities of the hands and feet wherein the digits fuse.
3
Deformities in stylopods.
4
No femur or patella formation.