The term 'genetic disease' generally conjures up an image of a chromosomal aberration often incompatible with life. or monogenic disorders inherited by classical Mendelian principles . These conditions are generally rare, but are considerably more common in exam situations.
It will be noted that there is considerable overlap between diseases as molecular techniques have often identified more than one gene defect which can result in an almost indistinguishable phenotype. This is not surprising if one considers the number of regulatory and biochemical pathways converging on a final outcome reflected in a limited number of disease end-points. In the tables, we have tried to illustrate the most common forms of inheritance and the most frequently implicated genes.