Question

What are some diseases or genetic abnormalities caused by dominant genes? Why are severe dominant genetic diseases rarer than recessive ones?

Answer 1

Examples of some dominant genetic diseases are: Marfan syndrome, polycystic kidney disease and Hungtinton's diseases.

Severe dominant genetic diseases are rarer than recessive ones due to the reason, that the heterozygous individual presents the condition and often dies without having an offspring. Whereas in recessive condition, the affected allele may be hidden in the heterozygous individuals and transmitted to the offspring until becoming homozygous.

In Huntington disease, the incidence is higher because many individuals have children before knowing that they are carriers of the dominant gene.