Tbox Factors in CHD

Question 1

The 5 Tbx Sub-families

Answer 1

• T
• Tbr1
• Tbx1
• Tbx2
• Tbx6

Question 2

Function

Answer 2

• Transcription activators or repressers

- Some have domains for both (T and Tbx4)

Question 3

Homeobox Sequence

Answer 3

• Sections of DNA found within genes involved in Morphogenesis

Question 4

Tbx5 Mutation

Answer 4

• Tbx5 is important in septation
• ASD and 1st Deg Heart Block
• Condition affecting bone formation in the upper limbs

Question 5

Tbx1 Mutation

Answer 5

• DiGeorge Syndrome (CATCH-22)
• Cardiac abnormalities (ToF, Truncus Arteriosus)
• Abnormal facies
• Thymic aplasia
• Cleft palate
• Hypocalcaemia/ hPTHism
• 22q11

Question 6

Tbx20

Answer 6

• Cardiac proliferation, regional specification and chamber formation, septation, valvulogenesis

Deletion
- Death from hypoplastic heart (mice E10.5)

Over-expression

• ASD, PFO and valve defects
• Up regulation of Tbx5, Cx40 and Cx43 (CCS genes)