Autosomal dominant disorders

Autosomal dominant disorders affect both males and females.
Mild or late onset conditions can often be traced through many
generations of a family. Affected people are heterozygous for
the abnormal allele and transmit this to half their offspring,
whether male or female. The disorder is not transmitted by
family members who are unaffected themselves. Estimation of
risk is therefore apparently simple, but in practice several
factors may cause difficulties in counselling families.