Variable expression
Expression: defect present in all cells, always expressed but in a variable way, e.g. Marfan syndrome is a connective tissue disorder: connective tissue is found in virtually all organs and parts of the body, which explains the major differences in expression.
In some cases a single gene defect may result in different clinical pictures in different individuals, even within the same family. We call these disorders with variable expression. Patients always have symptoms, although these vary from mild to severe.
Examples include Marfan syndrome and neurofibromatosis. e.g. Marfan syndrome is a connective tissue disorder: connective tissue is found in virtually all organs and parts of the body, which explains the major differences in expression.
