Question

What is/are the phenotypes when TBX5 is mutated at the cellular level? How is this genotype affect phenotype of the cell?

Answer 1

TBX5 gene encodes the T-box transcription factor that is responsible for regulating the developmental process of the cells. It helps in developing the heart chambers, the electrical conducting system and the septum of the heart. In the cellular level, inhibition of the expression ofTbx5 gene causes absence of forelimb buds.
Mutations in the Tbx5 gene results in a disorder called the Holt-Oram syndrome, that affects the heart and upper limbs. The phenotypic effect of the Tbx5 gene is - a hole in the heart or abnormal limb development. The ones with homozygous Tbx5 gene would not be able to survive gestation whereas the heterozygous ones would have abnormal development.