Table 1.

Antagonistically pleiotropic disease alleles.

Deleterious effect (disease)	Gene: variation	Benefit
Increased risk of cancers: ovarian (females), prostate (males).	AR: CAG trinucleotide repeat lengths.	Females: increased fertility via reduced degree of pre-mature ovarian failure, reduced risk of breast cancer. Males: increased number of viable sperm, reduced risk of Kennedy's Disease.
Huntington's disease.	HTT: CAG trinucleotide repeat lengths.	Increased fertility, decreased risk of certain cancers.
Sickle cell disease.	Hbb: various point mutations.	Protection against malaria in the heterozygous state.
Beta-thalassemia.	HB: various point mutations	Protection against malaria in the heterozygous state.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency.	G6PD: various missense mutations.	Protection against malaria.
Cystic fibrosis (CF)	CFTR: missense mutation.	Increased fertility.
Increased risk of osteoporosis in old age.	ALOX15: A:G intronic polymorphism.	Reduced risk of osetoporosis in youth.

These diseases are described in more detail in the text, the presence of an advantage in addition to the deleterious effects of the disease is well-supported by detailed genetic or epidemiological information.