Genetic Disorders Flashcards
Single Nucleotide Polymorphism is a DNA abnormality where variations are located at single isolated nucleotide positions. This is often biallelic. What does biallelic mean?
One of only two choices exist at a given site within population
Mechanism of microRNA in inhibiting gene expression
(A)mRNA cleavage
(B)preventing ribosomes fron reading it
Identify:
Photographic representation given as total number of chromosomes (arranged in decreasing length), followed by sex chromosome conplement, and then abnormalities in ascending numerical order
Karyotype
True or false. Small interfering RNA and microRNA have the same mechanism
True
True or false. All mutations manifest phenotypically
False
Identify
Heritable changes in gene expression that are not caused by alterations in DNA sequence
Epigenetics
Computer-based techniques that manage data on and analyze gene & protein expression
Bioinformatics
Measurement of all proteins expressed in a cell/tissue
Proteomics
Which is false? A. All genetic diseases are congenital. B. All congenital diseases are genetic. C. Both are false D. Both are true
C.
Some congenital diseases are not genetic, while some genetic diseases are not congenital.
Mutation where a single base is deleted
Point mutation
Mutation where 1-2 bases are inserted/removed
Frameshift mutations
Mutations that alter the meaning of sequence of encoded protein
Missense mutation
Mutation where amino acid codon is changed to a stop codon
Nonsense mutation
Differentiate conservative missense mutation from its non-conservative counterpart
Non-conservative : marked change in protein fxn
Mutations within noncoding sequence may lead to __
Marked reduction/total lack of transcription
Mutation that is characterized by amplification of a sequence of three nucleotides
Trinucleotide repeat mutation
True or false. The degree of amplification @ trinucleotide repeat mutation increases during gametogenesis
True
Mutations in single genes are also known as Mendelian disorders. Why?
They are consistent with the Laws of Segregration & Independent Assortment
False about autosomal dominant disorders
A. Patients always have infected parents
B. The person may inherit it but remain phenotypically normal
C. Variable expressivity is present in people with these diseases
A
Mutations involving egg or sperm may cause this
False about autosomal dominant disorders
A. Two defective genese have to be present
B. Expressed in heterozygotes
C. Unaffected people still can transmit disease to offspring
D. On average, Equal proportion of normal and affected offpspring
A
One is enough.
In autosomal dominant disorders, involved genes usually do not encode __
Enzyme proteins
Direct consequences of achondroplasia
Abnornality of cartilage formation
Shortened bones
Achondroplasia: mutation in ___
Fibroblast growth factor receptor 3
Specific mutation + gene mutated @ Marfan syndrome
Missense mutation at gene coding for fibrillin – 1(FBN1) on 15q21.1
Marfan syndrome : inherited disorder of __
Connective tissue
Neurofibromatosis-1 is also known as ___
von Recklinghausen’s disease
What are neurofibromas?
Benign tunors of peripheral nerves of Schwann cell origin
NF-1 is also characterized by pigmented lesions of the iris, aka __
Lisch nodules
NF-1 is characterized by areas of dark pigmentation on skin, also known as __
Cafe au lait spots
Familial hypercholestrolemia involes mutations in the gene encoding ____
LDL receptor
Gene encoding LDL receptor is located at __
Short arm of chromosome 19
False about autosomal recessive disorders
A. Only one allele is enough for disorder to manifest
B. Siblings may show disease
C. May be a product of consanguineous marriages
D. Onset is frequently early on in life
A
You need two
In autosomal dominant disorders, onset is frequently at adulthood. Yes or no?
Yes
In sickle cell anemia, the substitution happens at ___
6th position of beta globin chain
In sickle cell anemia, there is substitution of __ for __
Valine for glutamic acid residue
In phenylketonuria, this enzyme is lacking. High levels of Phenylalanine are present in the blood, therefore.
Phenylalanine hydroxylase
False about Y-linked disorders
A. Related to spermatogenesis
B. Infertile male
C. May be also transmitted via the mom
C
False about X-linked disorders
A. Females may only be homozygous
B. Lack of transmission from father to son
C. Most X-linked traits are recessive
A
Females may also be heterozygous
Fragile X syndrome may lead to inherited mental retardation. What kind of mutation happens here?
Expansion of CGG repeat @ Xq27.3 fragile site. Around 200 to 4000 repeats. Average is 29
Differentiate hemophilia A from hemophilia B
A - defect @ gene encoding for factor VIII
B - defect @ gene encoding for factor IX
Identify
Diseases that are consequences of additive effects of several abnormal genese and envt factors
Complex multigenic disorders
These immune cells are often used in karyotyping
Circulating lymphocytes
What is a metacentric chromosome?
Chromosome at the center –> 4 chromatids of equal length
What is a sub-metacentric chromosome?
Centromere is a little away from the center. One is slightly longer than the other.
What is a acrocentric chromosome?
Centromere closer to one end. Lengths of sides are very unequal.
What is a telocentric chromosome?
Centromere only at one end. One side only. Not in human cells
What is an aneuploid chromosomal abnormality?
Karyotype is not exact multiple of haploid number
What is monosomy?
Absence of one chromosome of homologous pair
What is trisomy?
Extra copy present in normally paired chromosome
Trisomy 21 is also known as __
Down Syndrome
Most conmon cause of trisomy 21 is meiotic nondisjunction. What is meiotic nondisjunction?
Failure of paired chromosome to separate and move to opposite poles of the spindle at anaphase
Trisomy 18 is also known as __
Edwards Syndrome
Trisomy 13 is also known as __
Patau syndrome
False about Klinefelter Syndrome
A. XXY
B. Dahil XX, female
C. Both are false
B
Male pa rin. Infertile lang.
Cri du chat syndrome has what kind of mutation?and in what part of what chromosome?
Deletion of the end of the p arm @ chromosome 5
False about Turner Syndrome
A. XXX
B. May come with primary amenorrhea
C. Female hypogonadism
A
X lang hehe
What is Huntington disease?
Repeats of guanine and cytosine nucleotides that occur in coding regions
[CHROMOSOMAL REARRANGEMENTS]
What is a translocation?
Part of chromosome transferred to another chromosome
