Given below is a pedigree chart showing the inheritance of a certain sex-linked trait in humans.
The trait traced in the above pedigree chart is

In the given chart the disease is inherited by female child from his father and none of the male child is affected hence it shows that the disease is X linked. Moreover, in the progeny the disease is expressed phenotypically by female child even if it is carrier, so the disease is dominant. Hence the pattern of disease is $\mathrm{X}$ linked dominant.