Zusammenfassung der Ressource
Genetic Disorders
- Single Gene
defect
(Structural)
- Sickle Cell
- Marfan Syndrome
- The protein that plays a
role in Marfan syndrome
is called fibrillin-1.
Marfan syndrome is
caused by a defect (or
mutation) in the gene
that tells the body how
to make fibrillin-1.
- TGF-β
- Autosomal Disorders
- Trisomy 21 (Down Syndrome)
- Most common, best
known Chromosome
know disease
- Most
Common
cause of
moderate
mental
retardation
- Congenital heart disease
- Celiac Disease
- 5-fold increase in
the risk of
leukemia (GATA1
mutations) on the
X chromosome
- Dementia-similar
to Alzheimer
disease (bAPP
gene on chr21)
- 47,XX or XY,+21 = 95%
- Trisomy 18 (Edwards Syndrome)
- wont make
it after a
year old,
Usually a
spontaneous
abortion
- Trisomy 13 (Patau Syndrome)
- wont make it after
a year old, Usually
a spontaneous
abortion
- X and Y
chromosome
aneuploidy
- Most common
defects in liveborn
infants XXY, XXX,
and XYY, these are
rare in
spontaneous
abortions
- Turner
Syndrome
- Most common in
chromosome
abnormality in
spontaneous
abortions
- MOST COMMON Monosomy
for 45 X (Female)
- Coarctation of the Aorta
(Narrowing of the Aorta)
- Webbed Neck
- Klinefelter
Syndrome
- Male with an
extra X
Chromosome
- Gynecomastia Excess development
of mammary grlands SOME but not
all
- Infertility
- 47,XXY (Male)
- Neurofibromatosis
(NF1)
- Chromosome #17
- Common
Autosomal
Dominant
disease
- half the cases are new
SPONTANEOUS rather than an
inherited mutation - functions as a
tumor suppressor gene
- Pleiotropic phenotype that
predisposes to benign and
malignant tumors of the nervous
system
- Cafe au lait
spots, Six or
more spots
- Nonmalignant peripheral nerve tumors
- Autosomal
Recessive
- - Cystic Fibrosis
1 child in 2,000
- Chromosome #7
- Tay-Sachs disease
- Jews in the
North America
- Neurological
disorder that
develops at 6
months
- Lysosomal storage disorder
- Inability to metabolize GM2 gangliosides
- Occurs only in
Homozygotes or
Compound
Heterozygotes --
NEEDS 2 MUTANT
ALLELES
- Autosomal
Dominant
- Familial
hypercholesterolemia
(FH)
- Populations of European and Japanese descent
- Mutations in the low-density lipoprotein (LDL) receptor
- premature coronary artery disease (CAD)
- It's rare homozygous patients, but much more severe
- X-Linked Recessive
- Only affect males
- phenotype
only expressed
in females that
are
Homozygous
- Hemophilia A
- lack of blood
clotting factor
VIII
- X-Linked = Mental retardation
- Daughters sons
HAVE A 50% chance
of the mutant X
- Daughters ALL
carriers
- X-Linked Dominant
- Rett syndrome
- MECP2, a
DNA-binding protein
known as
methyl-CpG-binding
protein 2
- Only females,
Insidious
- severe brain
disorder that
affects girls. It's
usually
discovered in
the first two
years of life
- Hemoglobinopathies
Anmerkungen:
- A blood disorder (such as sickle-cell anemia) caused by a genetically determined change in the
molecular structure of hemoglobin
- a-Thalassemias
- Chromosome #16
- Deletions
- Two identical alleles
- Results in mild
anemia and
microcytosis
- b-Thalassemias
- Chromosome #11
- Point Mutations
- Simple b-Thalassemia
- Accounts
for the
great
majority
of patients
- decrease in
the
abundance of
b-globin
mRNA
- mRNAs-have
premature stop
codons due to
single nucleotide
substitution
(Gln39Stop)
- β+ thalassemia
- Polyadenylation
defect (Bad
Substitution
AAUAAA to
AACAAA)
- Capping defect
(patient had A
to C
transversion)
- Anemia
- Hemoglobin Kempsey
- - Point
Mutation -
Higher O2
Affinity
- Sickle
cell
disease
Hb-S
- mutation due to amino
acid substitution
hemoglobin
- Normal
GAG to GTG
Sickle
- Beta6 GLU --> VAL Sickle ---> Hb-S
- First two years of life present with
anemia, failure to thrive,
splenomegaly, repeated
infections, and dactylitis
- ARE the
most
common
SINGLE
GENE
diseases in
humans
causes
substantial
morbidity
- Complex Thalassemias
- remove the b-globin
gene plus one or more
other genes or the LCR
= 19 KB
- HPFH
- Deletions with in b-Globin do not cause
Thalassmia but result in the phenotype
termed the hereditary persistence of fetal
hemoglobin (HPFH)
- benign condition
- Hb F (a2g2)
compensates
for the absence
of Hb A
- Williams Syndrome
- Deletion of about
26 genes long
arm (q) of
chromosome 7
- One of the
deleted genes
is elastin
- Elfin facial appearance
- Unusually
cheerful, ease
with strangers
- Supravalvular
aortic
stenosis