The genetic epidemiology of the form of microcephaly ascribed to mutation at the WDR62 locus

The disorder associated with mutation in the WDR62 gene MCPH2 is taken as the prototype of a condition which has a recessive mode of inheritance. The mutant homozygote has relatively lower fitness defined by the selection coefficient. Formulae which relate the incidence of the disorder to the mutation rate and the gene frequency in equilibrium when some degree of inbreeding occurs in the population are given.