Sickle Cell Andrew Novoa and Thea De Guzman

2/1/10

Per. 3

Summary Of Genetic Disorder What is the disorder?- An inherited genetic disorder of defective hemoglobin- When red blood cells form curved or sickle shapes - Tissue is damage and pain can be severe.Symptoms1.family members also have sickle cell2. fatigue, breathlessness, rapid heart rate,3.delayed growth and puberty, susceptibility to infections,4.Bloody urination, excessive thirst, excessive penis pain,5.Priapism, chest pain and decreased fertility.Interesting facts

-In the United States sickle cell is more common in African Americans. - About 70,000 Americans have sickle cell disease and another 2 million have sickle cell trait.-sickle cell disease is the most common inherited blood disorder.

Chromosome affected

• Chromosome 11

Mode of Inheritance

• Sickle cell disease is an inherited condition. • Two genes for the sickle hemoglobin must be inherited from one's parents in order

to have the disease.• A person who receives a gene for sickle cell disease from one parent and a normal

gene from the other has a condition called "sickle cell trait". • Sickle cell trait produces no symptoms or problems for most people.

- Autosomal recessive only happens when both parents are recessive but their child is dominant, creating a single copy of the mutated gene affecting the child with the disorder.

Alleles for sickle cell • People have 2 alleles for the hemoglobin

and hemoglobin has two parts to it, an alpha and a beta.

• Sickle cell is when a mutation in the beta subunit that codes for hemoglobin protein.

• -The Chromosome comes from you parents that carry the disorder and pass it to you.

-Recessive is represented with a lower case letter. A Dominant trait is represented by a upper case letter.

SS Ss

Ss ss

Ss Ss

Ss Ss

Ss Ss

ss ss

SS

s

s s sS

S

s s

S

s

Punnett square

Probability

SS SsSs ss

• Ratios • Homozygous Dominant • 1GG• Heterozygous Dominant • 2Gg• Homozygous recessive • 1gg• Percentages • Homozygous Dominant • 25%GG• Heterozygous Dominant • 50% • Homozygous recessive • 25%gg

sS

s

S

Punnett Squares

SS Ss

Ss ss

S s

S

s

• Meaning of Letters- Big S represents dominant allele so

little s represents the recessive allele.

• Phenotype - SS Normal - Ss Normal (sickle cell carrier)- ss Has sickle cell

• Genotype- SS is homozygous dominant (Normal)- Ss is Heterozygous dominant (Normal)- ss is Homozygous recessive (Sickle cell)

Punnett square Model

SS Ss

Ss ss

S s

S

s

• Phenotype • Ratios • 3 not affected 1 affected • Percentages• 75% Not affected 25% affected

• Genotypes • Ratios 1-SS, 2-Ss, 1-gg • Percentages • 25%-GG, 50%-Gg, 25%-gg