Genetic diseases are any hereditary disorders that result from a defect in an individual’s genetic material. The size of the defect in the genes can range from a small mutation affecting a single DNA base to a large alteration involving an entire chromosome or a group of chromosomes, such as the addition or deletion of a whole chromosome. In general, some genetic diseases are inherited from the father, mother, or both, while others occur due to a randomly acquired genetic mutation or environmental factors. Common Genetic Diseases Cystic Fibrosis: One of the most common genetic diseases, caused by a mutation in the gene responsible for regulating salt movement in and out of cells. This leads to thick mucus in the digestive, respiratory, and reproductive systems, along with increased salt in sweat. A child must inherit both defective genes from the father and mother to develop cystic fibrosis; inheriting only one defective gene makes the child a carrier, not affected. Sickle Cell Anemia: A common genetic disease resulting from inheriting a gene controlling red blood cells from both parents. It causes red blood cells to take a C-shape, making them unable to carry oxygen efficiently. These cells are also more viscous and can block blood vessels, leading to organ damage, severe fatigue, and anemia. Hemophilia: A hereditary bleeding disorder caused by a defect in clotting factors. It is linked to a mutation on the X chromosome, so the disease is passed from mothers to their male children, while females are carriers. Thalassemia (Mediterranean Anemia): A common hereditary disorder in the Mediterranean region, affecting hemoglobin production. It results in red blood cells that cannot carry oxygen efficiently. Patients often require regular blood transfusions depending on the severity of their condition. G6PD Deficiency: A genetic disorder caused by inheriting a gene on the X chromosome from one or both parents. It leads to a defect in producing the enzyme Glucose–6–Phosphate Dehydrogenase, which is essential for red blood cell function. Hemochromatosis: A hereditary disorder characterized by excessive iron absorption from food, leading to iron accumulation in vital organs such as the heart, kidneys, liver, and pancreas, impairing their function and potentially causing organ failure. Spinal Muscular Atrophy (SMA): This disease results from a genetic mutation in the SMN gene, which produces a protein essential for motor neurons in the spinal cord. Damage to these neurons leads to muscle wasting. Genetic Diseases in Children Down Syndrome: A common genetic disorder caused by the inheritance of an extra chromosome, resulting in 47 chromosomes instead of 46. Turner Syndrome: A genetic disorder affecting females, where the child inherits only one X chromosome instead of two (X instead of XX). DiGeorge Syndrome: Caused by a small deletion on chromosome 22. Marfan Syndrome: A disorder resulting from a mutation in the Fibrillin-1 gene on chromosome 15, which is necessary for connective tissue fiber formation. Autosomal Recessive Genetic Disorders These disorders require inheriting the defective gene from both parents. If only one defective gene is inherited, the person is a carrier but not affected. Notable autosomal recessive disorders include: Phenylketonuria (PKU): Caused by a mutation in the PAH gene, responsible for producing the enzyme phenylalanine hydroxylase. Without this enzyme, phenylalanine accumulates in the body and brain, causing damage. Severe Combined Immunodeficiency (Adenosine Deaminase Deficiency): Results from a mutation on chromosome 20 in a gene required for producing an enzyme essential for proper immune system function.
  الهدف الرابع : التعليم الجيد