Mutation rates of structural chromosome rearrangements in man

The gametic mutation rates of human structural chromosome rearrangements have been estimated from rearrangements ascertained from systematic surveys of live births and spontaneous abortions. The mutation rates for rearrangements that survive long enough to give rise to clinically recognized pregnancies are 2.20 X 10(-4) for balanced rearrangements, 3.54 X 10(-4) for unbalanced Robertsonian translocations, and 3.42 X 10(-4) for unbalanced non-Robertsonian rearrangements. These estimates give a mutation rate for all detectable structural chromosome rearrangements of approximately 1 X 10(-3). The most common single rearrangement, the Robertsonian translocation involving chromosomes 13 and 14, has a mutation rate of 1.5 X 10(-4).