What Mendel did not discover: exceptions in Mendelian genetics and their role in inherited human disease

Abstract

It has been one hundred and thirty-eight years after the initial publication of Mendel's laws of inheritance. Following a couple of decades of unprecedented progress in deciphering the molecular basis of human genetic disease, we have the luxury of hindsight to revisit Mendel's original discoveries in order to recognize variations in the themes that have otherwise endured the test of time. In this article we focus on diseases inherited in a Mendelian (or near Mendelian) fashion and describe deviations from the laws of Mendelian inheritance. We discuss relevant examples of inherited human disease and the underlying molecular mechanisms for the observed variations in Mendelian laws of inheritance.