Genetic Disorders Overview

Metafemale (Triple X Syndrome)

• Also known as Trisomy X, with 2n = 47, 44 autosomes + XXX
• Individuals are generally healthy, but slightly taller than average
• At risk for learning disabilities, but are fertile
• Caused by a random genetic error, not inherited

Cri-Du-Chat Syndrome

• Caused by a deletion of the short arm of chromosome 5
• Characterized by a high-pitched, cat-like cry
• Often associated with low birth weight, poor growth, severe cognitive, speech, and motor delays, and behavioral problems
• Not inherited, caused by a random event during formation of reproductive cells or early fetal development

Sickle-Cell Anemia (CSA)

• Hereditary single-gene disorder of the blood caused by a point mutation in the hemoglobin gene
• Causes normally disk-shaped red blood cells to become sickle or crescent-shaped
• Sickle-shaped red blood cells block blood flow in the blood vessels, leading to health problems

Hemophilia

• Blood-clotting ability is impaired due to mutation of genes on chromosome X
• Typical human karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes

Chromosomes

• Autosome: any chromosome not considered a sex chromosome (22 pairs in humans)
• Sex chromosome: involved in sex determination (XX: Female or XY: Male)

Genetic Disorders

• Aneuploidy: a change in the number of chromosomes
• Nondisjunction: the inability of homologous sex chromosomes to segregate during meiosis
• Genetic Disorder: caused by an abnormality in the genetic makeup of an individual
• Heritable Genetic Disorder: caused by mutations in the germ line (sex cells) and passed from parents to offspring
• Non-Heritable Genetic Disorder: caused by mutations in the DNA of the person

Down Syndrome (Trisomy 21)

• 2n = 47, with an extra chromosome 21
• Characterized by facial features, short stature, correctable heart defects, and developmental delays
• Most cases are not inherited

Klinefelter Syndrome

• 2n = 47, with 44 autosomes + XXY
• Boys and men are born with an extra X chromosome
• Characteristics: tall stature, poor muscle tone, reduced facial and body hair, small testes, and enlarged breasts
• In adulthood: infertility, low sex drive, and small testes
• Not directly inherited

Turner's Syndrome

• 2n = 45, with 44 autosomes + X
• Characterized by: no breast development, no menstrual periods, small ovaries, low sex hormones, infertility, and short stature
• Most have normal intelligence, and it is usually not inherited

Explore an overview of genetic disorders such as Triple X Syndrome and Cri-Du-Chat Syndrome. Learn about their causes, symptoms, and characteristics. Understand the implications and management of these genetic conditions.