Multifactorial inheritance is when more than 1 factor causes a trait or health problem, such as a birth defect or chronic illness. Genes can be 1 factor, but other things that aren't genes can play a part, too.

Detailed information on mosaic Down syndrome, including the chances for it to happen again in a family

Mosaicism is when a person has 2 or more genetically different sets of cells in his or her body.

Detailed information on mitochondrial inheritance and Leber's optic atrophy.

Detailed information on medical genetics, including chromosome abnormalities, single gene defects, multifactorial inheritance, teratogens, and non-traditional inheritance

Detailed information on the identification, treatment, and prevention of birth defects

Chromosome problems usually happen as a result of an error when cells divide.

When a chromosome is abnormal, it can cause health problems in the body. Tests called studies can look at chromosomes to see what type of problem a person has.

A birth defect is a health problem or abnormal physical change that is present when a baby is born. Birth defects can be very mild, where the baby looks and acts like any other baby. Or birth defects can be more severe. Read on to learn more.

Detailed information on visual screening tests in children