DISORDERS

• Single-gene Disorders - is a mutation that affects only one gene. It is also known as Mendelian / Monogenetic Inheritance. SGD has several patterns of genetic inheritance

  SGD has several patterns of genetic inheritance
• Single-gene Disorders

  Genetic Disorder:

  • Cystic Fibrosis

  Genotype:

  • Autosomal recessive

  Phenotypic Effects:

  • life-threatening respiratory illness and blockage; digestive problems; salty sweat
• Single-gene Disorders

  Genetic Disorder:

  • Sickle Cell Anemia

  Genotype:

  • Autosomal recessive

  Phenotypic Effects:

  • sickle-shaped red blood cells; reduced oxygen- carrying capacity
• Single-gene Disorders

  Genetic Disorder:

  • Huntington's Disease

  Genotype:

  • Autosomal Dominant

  Phenotypic Effects:

  • neurological disease fatal in middle-aged; uncontrollable twitching
• Single-gene Disorders

  Genetic Disorder:

  • Red-Green Colorblindness

  Genotype:

  • X-linked recessive

  Phenotypic Effects:

  • inability to distinguished color red and green; reduced night vision
• Single-gene Disorders

  Genetic Disorder:

  • Hemophilia A

  Genotype:

  • X-linked recessive

  Phenotypic Effects:

  • lack of blood-clotting; can result in fatal hemorrhage
• Chromosomal Disorders - a mutation where a chromosome (or parts of chromosomes) are missing or changed. Nondisjunction occurs when homologous chromosomes or sister chromatids fail to separate during meiosis, resulting in an abnormal chromosome number
• Chromosomal Disorders

  Genetic Disorder:

  • Down Syndrome

  Genotype:

  • extra copy (complete or partial) of chromosome 21

  Phenotypic Effects:

  • developmental delays, distinctive facial appearance, and other abnormalities
• Chromosomal Disorders

  Genetic Disorder:

  • Turner's Syndrome

  Genotype:

  • one X chromosome but no other sex chromosome (XO)

  Phenotypic Effects:

  • female with short height and infertility (inability to reproduce)
• Chromosomal Disorders

  Genetic Disorder:

  • Triple X Syndrome

  Genotype:

  • three X chromosomes (XXX)

  Phenotypic Effects:

  • female with mild developmental delays and menstrual irregularities
• Chromosomal Disorders

  Genetic Disorder:

  • Klinefelter's Syndrome

  Genotype:

  • one Y chromosome and two or more X chromosomes (XXY, XXXY

  Phenotypic Effects:

  • male with problems in sexual development and reduced levels of the male hormone testosterone