Possible Mechanisms of Congenital Malformations

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Primary events

Malformation

• At molecular level Head

• Intrinsic abnormalities of the cell

• Biochemical function

• Intracellular signal transduction

• Regulation of cell proliferation, differentiation, and death

• Abnormal tissue/cell induction

• Via direct cell/tissue contact

• Via soluble signal molecules

• At histologic level Head

• Agenesis

• Hypoplasia

• Hyperplasia and hypertrophy

• Cells generated in wrong time

• Cells generated in wrong place

• Destruction of primodial tissue

• Abnormal programmed cell death

• Too much

• Too little

• Premature

• Delayed

• Dysplasia

• Abnormal migration

• Failure for tissue to fuse

• Atresia or obstruction

• Abnormal dendritic and/or axonal architecture

• Abnormal connection and division of tracts

 Disruption/Destruction Head

 Deformation Head

Secondary and tertiary events sequential to the primary event Head

NeuroLearn NeuroHelp Malformations  For Comment: KarMing-Fung@ouhsc.edu