Download Sickle Cell Anemia

By: Dasia Davis
Gabriella Mirenda
Lorena Sposato
Inherited blood disorder that affects red blood cells
 Red blood cells contain Hemoglobin S which is abnormal
- Become sickle shape and makes it difficult fitting through small blood
vessels and less blood reaches body.
 Symptoms of sickle cell include
1. Abdominal Pain
2. Delayed growth and puberty
3. Bone Pain
4. Breathlessness
5. Fever
6. Jaundice
7. Paleness
8. Ulcer in the lower legs
Interesting facts:
with each pregnancy, 2 people have sickle cell traits have:
 A 25% chance of having an unaffected child with normal hemoglobin
 A 50% chance of having a child who also is a carrier.
 A 25% chance of having a child with sickle cell anemia

 The
HBB gene is found in the region 15.5 on
the short (p) arm of human Chromosome 11.
 Autosomal
Recessive genetic disorder
 Two copies of the altered gene must be
present on the autosomes in order for the
person to be affected by the trait.
2
alleles, one from each parent
 Alleles are represented by:
-RR Rr rr
 Dominant- expressed in a person with only
one copy of that gene present.
 Recessive- expressed in a person with two
copies of the gene is present.
S s
S SS Ss
s Ss ss
d
d
Dd
Dd
D
D Dd Dd
Ratios:
Homozygous dominant: Heterozygous dominant: Homozygous recessive
1 : 2
: 1
1SS
:
:
2Ss
1ss
Homozygous dominant: Heterozygous dominant: Homozygous recessive
25% : 50% : 25%
:
50%Ss
S SS Ss
s Ss ss
Percentages:
25% SS
S s
:
25% ss
 SS
represents the dominant allele SICKLE and s
represents the recessive allele
 Phenotype:
 SS= Sickle Cell disease
 Ss= Sickle cell carrier
 ss=No trace
 Genotype:
 SS=Homozygous dominant
 Ss=Heterozygous dominant
 Ss=Homozygous recessive
S s
S SS Ss
s Ss ss
 Phenotype
-Ratios- 3SS: 1ss
-Percentages: 75% SS: 25% ss
 Genotype
-Ratio- 1SS: 2Ss: 1ss
-Percentages- 25% SS: 50%Ss: 25%ss
S s
S SS Ss
s Ss ss
Father’s Genes
M
O
T
H
E
R’
S
G
E
N
E
S
S s
S SS Ss
s Ss ss
Genotype:
Ratio: 3SS: 1ss
Percentage: 75%SS: 25% ss
Phenotype:
Ratio:1SS: 2Ss: 1ss
Percentage:25%SS: 50%Ss:
25%ss
Ricky
Martin
Sarah
Carl
Lizzie
Alex
Miranda
Cashmere
Vanessa
Bob
Marley
Red= Person is Healthy,
with a possible chance of
carrying a “bad” gene.
Yellow= Person is affected
KEY
Bob
Kim
Brian
Lily
Gaby
Kait
Charlie
Ana
Questions:
1.) How many sickle cell genes are need to
inherit the disease?
2.) What does it mean, when a person is a
“carrier” of the gene?

Circle: Female

Square: Male

All Red: Person is healthy.

All Yellow: Person is
affected.

Red/Yellow: Carrier.
Jen
Ben
Susan
Answers:
• It occurs when a person inherits
two sickle cell genes.
• It means the person carries one “bad” gene
and one “healthy” gene, but is essentially
healthy and has no symptoms of the disease.