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Galactosemia. Name: Olivia Taylor, Julia D, and Varsha M. Date: January 28, 2010 Period: 3. Summary of Galactosemia. Is an inherited disease that makes the host unable to metabolize galactose. Galactose - is a simple sugar, found in ½ of milk.

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Galactosemia

Galactosemia

Name: Olivia Taylor, Julia D, and Varsha M.

Date: January 28, 2010

Period: 3


Summary of galactosemia
Summary of Galactosemia

  • Is an inherited disease that makes the host unable to metabolize galactose. Galactose- is a simple sugar, found in ½ of milk.

  • People with Galactosemia either don’t have, or lack the enzyme (GALT) that helps break down galactose.

  • Infants that inherit Galactosemia who are feed dairy/milk products will have jaundice, vomiting, lethargy, and also mental retardation, cirrhosis, and kidney failure can occur.

    Did You Know

  • Children with Galactosemia have lower (IQ) levels then their siblings, and that most girls with it, can’t conceive naturally. Though boys have normal testicular function.



Mode of inheritance
Mode of Inheritance

  • How do you get this disorder?

    • Autosomal recessive pattern

    • To get this disorder, a child must get one defective gene from each parent

    • If the child inherits one normal & one bad gene, they are okay. But can still pass the bad one to their kids. This gives their child another possibility of having Galactosemia.

  • What’s an Autosomal Recessive?

    • Is when a child has to get a copy of a gene from each parent to have that trait

  • What’s an Autosomal Dominant?

    • Is when a child has to only get one defected gene from one parent to inherit a disease

  • What’s Sex linked/X-linked?

  • Is when a gene gets carried on a sex chromosome, especially an x-chromosome

    • XX- Female

    • XY-Male

    • Determines sex & sex characteristics


What are alleles
What are Alleles

Alleles are represented by a small letter on the punnett square. -Capital letters are dominant, and lower case letters are recessive.

• Alleles are a way to identify in a gene pair, which gene produces what phenotypes. You get them from your parents

• Depending on the disease a small letter (Alleles) can be good or bad genes. In our disease it is bad.

• Example: In order to have Galactosemia you need two bad genes, or two small Alleles, or recessive(aa) genes. Having two of the same genes (aa) is called a homozygous pair. To be a carrier you need a dominant and a recessive gene (Aa), having a bad and a good genes is called a Heterozygous pairs.


Punnett squares to show the possibility of each child receiving the galactosemia gene
Punnett squares to show the possibility of each child receiving the galactosemia gene

Father

Father

  • gg= homozygous recessive (has the complete galactosemia gene)

  • GG= homozygous dominant (does not have the gene at all)

  • Gg= heterozygous dominant (Has a carrier of the gene but it does not show)

  • Remember each punnett square is the possibility for EACH child to get the galactosemia gene!

  • The Father is on the top of the punett square and the mother is on the left of the punnett square.

M

O

T

H

E

r

M

O

T

H

E

R


Punnett square to explain probability with ratios and percentages
Punnett Square to explain probability with Ratios, and Percentages.

  • Ratios-

    1gg1GG2Gg

    Homozygous recessiveHomozygous dominantHeterozygous dominant

  • If you add them up they should = 4 because there are only 4 possibilities

  • Percentages-

    Homozygous recessiveHomozygous dominantHeterozygous dominant

    25%25%50%

    gg GG Gg

  • All the percentages added must equal 100%, because there are four boxes each representing 25%


What each letter represents Percentages.G is the dominant allele g is the recessive allele Phenotype is what we would seeGG = No Galactosemia geneGg = No Galactosemia gene but with a carriergg = Galactosemia geneGenotype is what is in our genesGG is Homozygous dominant (no Galactosemia gene)Gg is Heterozygous dominant (Galactosemia gene)gg is homozygous recessive (Galactosemia gene)

Here we use the punnett squares to show what we can see and what is in our genes

Father

Mo t he r

Father

Mo t he r


Using punnet square
Using Punnet Square Percentages.

Father

Mo t he r


Student practice punnett square practice
Student Practice Percentages.Punnett Square Practice

G

g

Genotype:

Ratio:

Percentage:

Phenotype:

Ratio: ¼

Percentage: 25%

G

g


Lastly a 3 generation hypothetical pedigree
Lastly, a 3 generation hypothetical pedigree Percentages.

Autosomal Dominant

Autosomal recessive

X-Linked

Glactosemia male

All orange square:gene is bad on X chromsome,

Normal male

All white square: gene is good on X chromsome.

Glactosemia female

All orange circle: gene is bad on X chromsome

Carrier Glactosemia Female

½ orange, ½ white: Carrier of Glactosemia, bad gene on X, or Y. Is fine, but is a carrier, meaining having a good and bad gene.

All Orange :Person has two bad genes, is infected.

All white: Person may be a carrier of disorder, but is fine.

Circle: Female Square: Male

All White: Person has two healthy genes

½ Orange, ½ white: Person is a carrier, has one good gene and one bad gene

All Orange: Person has the disease, has two bad genes


Student practice
Student Practice Percentages.

Circle: Female Square: Male

All White: Person has two healthy genes

½ Orange, ½ white: Person is a carrier, has one good gene and one bad gene

All Orange: Person has the disease, has two bad genes