Char syndrome Fewer than 10 mutations in the TFAP2B gene have been identified in people with Char syndrome. These mutations alter the structure of transcription factor AP-2β. More than half of the known mutations alter a region of the protein that is critical for DNA binding. Other mutations occur in an area of the protein that is necessary for regulating gene activity. At least two changes in the TFAP2B gene prevent the production of any transcription factor AP-2β. A loss of this protein's function disrupts the normal development of structures derived from the neural crest, including the heart and facial features. Abnormal development of these tissues leads to the major features of Char syndrome. other disorders Studies suggest that several normal variations (polymorphisms) in the TFAP2B gene are associated with an increased risk of type 2 diabetes mellitus, the most common form of diabetes. People with this disease have high blood sugar levels because the body does not respond correctly to insulin, a hormone produced by the pancreas. This hormone controls how much sugar (in the form of glucose) is passed from the bloodstream into cells to be used as energy. Researchers have proposed that polymorphisms in the TFAP2B gene alter cells' responsiveness to insulin, particularly fat-storing cells (adipocytes). Although changes in the TFAP2B gene may be associated with type 2 diabetes mellitus, a combination of lifestyle, genetic, and environmental factors all play a part in determining the risk of this complex disorder.

     The TFAP2B gene provides instructions for making a protein called transcription factor AP-2β. A transcription factor is a protein that attaches (binds) to specific regions of DNA and helps control the activity of particular genes. Transcription factor AP-2β is one of a group of related proteins called AP-2 transcription factors. These proteins regulate genes that help control cell division and the self-destruction of cells that are no longer needed (apoptosis). Transcription factor AP-2β is involved in development before birth. In particular, this protein is active in the neural crest, which is a group of cells in the early embryo that give rise to many tissues and organs. Neural crest cells migrate to form portions of the nervous system, glands that produce hormones (endocrine glands), pigment cells, smooth muscle and other tissues in the heart, and many tissues in the face and skull. Transcription factor AP-2β also appears to play an important role in the development of the limbs.

The following transcription factors affect gene expression:

• ER-alpha

Molecular Function:

• Chromatin Binding
• Cysteine-Type Endopeptidase Inhibitor Activity Involved In Apoptotic Process
• Dna Binding
• Enhancer Sequence-Specific Dna Binding
• Protein Dimerization Activity
• Protein Heterodimerization Activity
• Protein Homodimerization Activity
• Rna Polymerase Ii Core Promoter Sequence-Specific Dna Binding
• Rna Polymerase Ii Transcription Coactivator Activity
• Rna Polymerase Ii Transcription Corepressor Activity
• Rna Polymerase Ii Transcription Factor Activity, Sequence-Specific Dna Binding
• Sequence-Specific Dna Binding
• Transcriptional Activator Activity, Rna Polymerase Ii Core Promoter Proximal Region Sequence-Specific Binding
• Transcription Coactivator Activity
• Transcription Corepressor Activity
• Transcription Factor Activity, Rna Polymerase Ii Core Promoter Sequence-Specific
• Transcription Factor Activity, Sequence-Specific Dna Binding

Biological Processes:

• Aorta Morphogenesis
• Calcium Ion Homeostasis
• Cellular Ammonia Homeostasis
• Cellular Creatinine Homeostasis
• Cellular Urea Homeostasis
• Collecting Duct Development
• Distal Tubule Development
• Ductus Arteriosus Closure
• Fat Cell Differentiation
• Forelimb Morphogenesis
• Glucose Homeostasis
• Glucose Metabolic Process
• Hindlimb Morphogenesis
• Kidney Development
• Magnesium Ion Homeostasis
• Metanephric Nephron Development
• Negative Regulation Of Apoptotic Process
• Negative Regulation Of Cell Proliferation
• Negative Regulation Of Cysteine-Type Endopeptidase Activity Involved In Apoptotic Process
• Negative Regulation Of Neuron Apoptotic Process
• Negative Regulation Of Transcription, Dna-Templated
• Negative Regulation Of Transcription From Rna Polymerase Ii Promoter
• Phosphate Ion Homeostasis
• Positive Regulation Of Cell Proliferation
• Positive Regulation Of Neuron Apoptotic Process
• Positive Regulation Of Transcription, Dna-Templated
• Positive Regulation Of Transcription From Rna Polymerase Ii Promoter
• Positive Regulation Of Urine Volume
• Potassium Ion Homeostasis
• Regulation Of Bmp Signaling Pathway
• Regulation Of Cell Differentiation
• Regulation Of Insulin Secretion
• Regulation Of Transcription, Dna-Templated
• Renal Water Homeostasis
• Response To Lithium Ion
• Retina Layer Formation
• Skin Development
• Sodium Ion Homeostasis
• Sympathetic Nervous System Development