Genetic Disorders

Genetic Disorder

Cystic fibrosis

Albinism

Tay-Sachs

Sickle-cell disease

Achondroplasia

Polydactyly

Genetic Basis

Autosomal recessive

Symptoms

Frequencies in Population

Excessive mucus production causes lung infections, and affects other organs; poor nutrient absorption; chronic bronchitis; foul stools; bacterial infections

1 out of every 2500 people of European descent; rare in other groups

fewer than five people per 100,000 in the United States and Europe; Other parts of the world have a much higher rate

Autosomal recessive

lack of melanin pigment in the eyes, skin and hair; increased susceptibility to skin cancers and vision problems

Autosomal recessive

relentless deterioration of mental and physical abilities occurs; cognitive, motor, speech difficulties, swallowing difficulties, unsteadiness of gait, and spasticity

Disproportionately high among Ashkenazic Jews – about 1 for every 3600 births; much less in other non-Jews

One out of 10 AfricanAmericans; in general, 1 in 5,000

Autosomal recessive

sickle-shaped red blood cells that obstruct capillaries and restrict blood flow to an organ, resulting in ischemia, pain, and often organ damage

Autosomal dominant

Autosomal dominant

Huntington’s disease

Autosomal dominant

Phenylketonuria (PKU)

Autosomal recessive

Hemophilia

Sex-linked recessive

Achondroplastic dwarfs have short stature, with an average adult height of 131 cm (4 feet, 3.8 inches) for males and 123 cm (4 feet, 0.6 inches) for females

Extra fingers or toes, usually a soft tissue without joints

uncoordinated, jerky body movements and a decline in some mental abilities; deterioration of nervous system Inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet to avoid mental retardation. Caused by the absence of one or more proteins necessary for normal blood clotting Red-green color blindness is rarely more than an

1 in 25,000

1 in every 500 live births; 2.3 per 1000 in white males, 0.6 per 1000 in white females, 13.5 per 1000 in black males, and 11.1 per 1000 in black females

One in 10,000 people

One per 25,000 people

Hemophilia A occurs in about 1 in 5,000–10,000 male births[2], while Hemophilia B occurs at about 1 in about 20,000–34,000 Varies in populations

Color blindness

Sex-linked recessive

Duchenne muscular dystrophy

Sex-linked recessive

Progressive weakening of muscle control and loss of coordination

Down syndrome

47 chromosomes due to trisomy 21

Characteristics facial features, mental retardation, prone to developing Alzheimer’s and leukemia

Turner’s syndrome

XO – 45 chromosomes due to a missing sex chromosome

Smaller stature, possible mental retardation

XXY – 47 chromosomes due to an extra X chromosome

Have male genitals, but testes are abnormally small and the men are sterile

Klinefelter’s syndrome

inconvenience, as it does not harm the body physically

1 in 3500 births

1 per 800-1000 births

1 in 2500 girls

1 in 500 males