Why are lethal dominant disorders so rare?

Lethal dominant disorders are rare because they typically result in early embryonic lethality or severe health issues that prevent affected individuals from surviving to reproductive age. In these disorders, only one copy of the mutated gene is needed to manifest the condition, but if the mutation is lethal, it often leads to miscarriage or death shortly after birth. Consequently, the genes responsible for these disorders are not passed on to future generations, limiting their prevalence in the population.