Genetic Disorders By Tanner and Jack Definition A

Genetic Disorders By: Tanner and Jack

Definition • A disease that is caused by an abnormality in a an individual's DNA.

Level 1: Single-Gene Disorders • Disorders result when a mutation causes the protein product of a single gene to be altered or missing. • Examples: Cystic fibrosis, Sickle cell disease, Neurofibromatosis 1, etc…

Level 2 - Chromosome Abnormalities In these disorders, entire chromosomes, or large segments of them, are missing, duplicated, or otherwise altered. Examples: Williams Syndrome, Down Syndrome, Maple Syrup Urine Disease, Huntington’s disease, etc…

Level 3: Multifactorial Disorders • Multifactorial disorders result from mutations in multiple genes, often coupled with environmental causes. • Examples: Alzheimer’s disease, Breast/Ovarian cancer, Colon cancer, etc…

Recessive Disorders • Most human genetic disorders are recessive • Heterozygous and homozygous recessive parents can transfer to childeren • Most people with disorders receive it from their parents who are both heterozygotes, or carriers of the recessive allele

Albinism • Symptoms include lack of pigment in skin, hair, and eyes • 1/22, 000 people

Cystic Fibrosis • Symptoms include excess mucus in lungs, digestive tract, liver, an increased susceptibility to infections, and death in early childhood unless treated • 1/1, 800 European-Americans

Phenylketonuria (PKU) • Symptoms include accumulation of phenylalanine in blood, lack of normal skin pigment, mental retardation unless treated • 1/10, 000 in U. S. and Europe

Sickle-cell Disease • Symptoms include sickled red blood cells, and damage to many tissues • 1/500 African-Americans

Tay Sachs Disease • Symptoms include lipid accumulation in brain cells, mental deficiency, blindness, and death in childhood • 1/3, 500 European Jews

Dominant Disorders • Much less common than recessive disorders. • Heterozygous and Homozygous dominant parents can transfer to children

Achondroplasia (Dwarfism) • Head and torso develop normally while the arms and legs are short. • Homozygous dominant genotype results in death of the embryo. • Only heterozygotes have this disorder. • Those with achondroplasia have a 50% chance of passing the condition to their children • 1/25, 000

Alzheimer’s Disease • Symptoms include mental deterioration that usually happens later in life. • Likelihood is unknown.

Huntington’s Disease • Symptoms include mental deterioration and uncontrollable movements that usually strike in mid-aged people. • Once deterioration begins, it is irreversible and fatal. • Any child born to a parent with the allele has a 50% chance of inheritance. • 1/25, 000