Genetic Conditions

Nondisjunction is a chromosomal mutation that causes a person to have an abnormal number of chromosomes.

Huntington's disease is caused by a rare dominant allele.

You need 2 copies of the recessive allele to express a recessive disorder.

Down's syndrome results from having 3 copies of chromosome pair 21.

Sickle cell anemia is caused by recessive alleles and a substitution mutation.

A recessive allele is an allele that must be present in two copies for its trait to be expressed.

A dominant allele is an allele that can express its trait even when only one copy is present.

Huntington's disease is caused by a mutation in the HTT gene, which is inherited in a dominant manner.

Nondisjunction can lead to aneuploidy, resulting in disorders such as Down's syndrome.

Sickle cell anemia is inherited in an autosomal recessive pattern.