Genes Recesivos y Dominantes

Dominant Genetic Disorders

The affected parent has a single defective gene (D), which dominates its normal counterpart (n). Each child has a 50 percent risk of inheriting the faulty gene and thedisorder.
Disorders:
Polydactyly – A fairly common problem in which the child has extra fingers or toes. It can be corrected by surgery. Prenatal testing cannot detect this problem in most cases.Achondroplasia – A very rare abnormality of the skeleton in which the arms and legs are shorter than normal. This can be detected by ultrasound.
Huntington disease – A problem with the nervous systemthat causes loss of control over movements and mental function, usually starting in midlife. Prenatal testing is possible.

Recessive Genetic Disorders

Both parents carry a singledefective gene (d) but are protected by the presence of a normal gene (N), which is generally sufficient for normal function. Two defective copies of the gene are required to produce a disorder. Each child has a 50percent chance of being a carrier like both parents and a 25 percent risk of inheriting the disorder.
Disorders:
Cystic fibrosis – A condition that causes very thick mucus to be produced in the lungs,clogging them and causing lung disease. It also causes problems with the pancreas. It occurs most often in whites.
Sickle cell disease – A disease that causes the red blood cells to take on acrescent, or "sickle" shape. These abnormal cells tend to get stuck in the blood vessels. This cuts off oxygen to tissues and causes pain. Anaemia [blood that is low in red blood cells] often occurs. Thesedisease affects mostly African Americans. ·
Tay-Sachs disease – A disease that first appears at about 6 months of age and causes mental retardation. Blindness, seizures , and death within a few years.It is found mostly in persons of eastern European Jewish descent [Ashkenazi Jews]. ·
Thalassemia – A condition that causes anaemia. One form [beta-thalassemia] occurs most often in persons of...