Genetic Disease Flashcards
How many protein-encoding genes are in the human genome?
19,000
T/F: Permanent change in the germ cells can be inherited.
True
Permanent DNA damage in the _______ cells may result in a tumor or developmental abnormality.
Somatic
Autosomal dominant, autosomal recessive, and sex-linked disorders are all __________ disorders.
Mendelian
What are cytogenetic disorders?
Involve chromosomal aberrations: autosomes or sex chromosomes
T/F: Different mutations at different spots on a gene will always have unique manifestations.
FALSE
Huntington’s disease is an autosomal __________ disorder.
Dominant
What is incomplete penetrance?
Person has a mutant gene but doesn’t or only partially extremes it phenotypically
What is variable expressively?
Expression can be identified in all affected persons, but to differing extents
What is a new or “de novo” mutation?
Neither parent affected/no family history
What is an example of an autosomal dominant disease withe variable expressivity?
Neurofibromatosis
What is the largest group of Mendelian disorders?
Autosomal recessive
Many AR conditions are ________ defects, leading to __________ dysfunction.
Enzyme; metabolic
What one trait may be linked to the Y chromosome?
Hairy ears
NO DISEASES
T/F: In x-linked disorders, women will more often express the disease.
FALSE
Women have another X-chromosome to protect them.
What is a common example of an X-linked disorder?
Hemophilia A
Describe lyonizations and unfavorable lyonizations?
Lyonization: one of the X chromosomes from the mom will be inactivated (normally results in mixture of active maternal and paternal X chromosomes)
Unfavorable lyonizations: inactivation of high number of normal X chromosomes may result in X-linked disease expression in a heterozygous female
Marian syndrome is an ___ disorder involving in a mutation with the ______ gene.
AD; FBN1
What are some complications of Marfan syndrome?
Aortic aneurysm and dissection
Which disease causes a problem with collagen synthesis? These patients may be circus performers due to their stretchable skin.
Ehlers-Danlos Syndromes
Familial hypercholesterolemia is due to a genetic disorder of the ____ receptor.
LDL
Cystic fibrosis is caused by a genetic disorder of the _______ channel protein.
chloride
Familial hypercholesterolemia is seen in how many people?
1 in 500
Patients will develop early atherosclerosis, especially if they are homozygous, for which disease?
Familial hypercholesterolemia
A 20 year old patient dies of myocardial infarction due to an atherosclerosis. Which disease lead to this?
Homozygous for familial hypercholesterolemia
Phenylketonuria, galactosemia, and lysosomal storage diseases are all caused by mutations in _______ proteins.
Enzyme
Phenylketonuria is an ____ disorder. It will often cause ______________ by 6 months of birth.
AR; mental retardation
How would you treat phenylketonuria?
Restrict diet of phenylalanine
Accumulation of large insoluble molecules in macrophages leads to neuronal damage and other neural problems in a young child. What is the disorder?
Lysosomal storage disease - mutated enzyme
Mucopolysaccharide storage disease is a type of _________ storage disease?
Lysosomal
Which disease is caused by a deficiency of alpha-L-iduronidase?
Hurler Disease
________ is an X-linked disease caused by a deficiency of L-iduronate sulfatase.
Hunter
T/F: Hunter disease often has a much better outlook than Hurler disease.
TRUE
How many newborns has a chromosomal abnormality?
1 in 200
A normal chromosome count (2 x 23 = 46) is termed _________?
Euploid
An increase in chromosome count that is a multiple of that normally seen (i.e. 3 x 23) is termed __________ and generally results in abortion.
polyploidy
Any number that is not an exact multiple of the normal chromosome count is termed _______.
Aneuploidy
Having one extra chromosome is termed _________.
Trisomy
Having one less chromosome is termed _________>
Monosomy
____________ is transfer of a part of one chromosome to another nonhomologous chromosome.
Translocation
When fragments are exchanged between two chromosomes it is termed _________ translocation.
Reciprocal
_________ is the loss of a portion of a chromosome.
Deletion
__________ is when the chromosome breaks in two points, then the released fragment is reunited after a complete turnaround.
Inversion
What is trisomy 21?
Down Syndrome
What are the odds of having a child with Down Syndrome if a mother is over 45 years old?
1 in 25
What is Klinefelter syndrome?
Sex chromosome disorder where the patient is phenotypically male but genotype is XXY
Female hypogonadism is a major symptom of ___________.
Turner syndrome
What are some prenatal indications for genetic analysis?
- Mothers age >40
- Parent is carrier
- Hx of previous child with abnormality
Postnatal indications for genetic analysis?
- Multiple congenital abnormalities
- Infertility
- Multiple miscarriages
- Unexplained developmental problems
- Suspected aneuploidy
What is the major symptom of Klinefelter syndrome?
Hypogonadism and sterility
What is a dental related symptom of Klinefelter syndrome?
Taurodontism = enlarged pulp
What is different about the genotype of someone with Turner syndrome?
Only has one X chromosome
What are some symptoms of Turner syndrome?
- Short
- Shield-like chest
- High arched palate
- Cardiovascular problems
- No secondary sex characteristics
What is a point mutation and example of disease from point mutation?
Single nucleotide base. Sickle cell
What is a frame shift mutation?
Insertion or deletion of 1 or 2 base pairs, altering the reading frame of DNA
What is a trinucleotide repeat mutation and an example of a disease?
Amplification of sequence of 3 nucleotides. Fragile X syndrome
What are epigenetic changes?
Modulation of gene expression without altering DNA sequence
What happens when promoter regions are methylated? This is an example of what?
Makes them inaccessible to RNA polymerase = reduced expression.
Epigenetics
When is the age of onset typically for AR diseases?
Early in life
T/F: Complete penetrance is common in autosomal recessive disease.
True
What may cause a heterozygous female to demonstrate full expression of a X-linked disease?
Unfavorable lyonization
Who would be affected by an X-linked dominant disorder?
Heterozygous, homozygous, and hemizygous
What is an example of an X-linked dominant disorder?
Oral-Facial-Digital syndrome
What are some examples of Lysosomal Storage diseases?
- Tay-sachs
- Niemann-Pick
- Gaucher
- Mucopolysaccharidoses
What are three ways to diagnose genetic diseases?
- Fluorescence in situ hybridization (FISH) - recognize specific sequences
- Comparative genomic hybridization - compare to normal DNA
- Molecular diagnosis (PCR, restrictions enzyme, fluorescence)
