Test Bank for Genetics Analysis and Principles
WITH 100% ERIFIED QUESTIONS AND ANSWERS
Osteogenesis imperfecta type I is the mildest form of osteogenesis imperfecta because
most of the mutations that cause osteogenesis imperfecta type I: - Result in no protein
being produced from one allele (null allele)
Duchenne and Becker muscular dystrophies result from mutations in the gene for
dystrophin. The diseases differ in onset and severity, but not in inheritance pattern.
They should therefore be considered: - Allelic diseases-- this is allelic heterogeneity
Two maternal uncles with a clinical picture similar to the affected male child shows
______ inheritance - X-Linked recessive
Advanced paternal age increases risk of which mutations? - New autosomal dominant
mutations
Advanced maternal age increases risk of? - Chromosomal aneuploidy
Recurrent early pregnancy losses are often due to? - Chromosomal rearrangement
Consanguinity increase the risk of? - Autosomal recessive inheritance
What term refers to the Classic forms of single-gene inheritance - Mendelian
What term refers to the Inheritance pattern of a gene on an X or Y chromosome - Sex-
Linked
What term refers to inactivation of a gene or genes dependent upon the gender of the
transmitting parent - Imprinting
What is inheritance of extra-nuclear genetic material called? - Mitochondrial inheritance
In which kind of inheritance are parents obligate carriers? - Autosomal recessive
inheritance
What is having only one allele at a locus referred to as? - Hemizygous
A specific combination of linked alleles is called? - Haplotype
Which ethnic group most often gets alpha-thalassemia? - Asians
, Which ethnic group most often gets beta-thalassemia? - Mediterraneans
Which ethnic group most often gets Gaucher's disease? - Ashkenazic Jews
Which ethnic group most often gets PKU? - Caucasians
A patient has Duchenne Muscular Dystrophy (DMD) because exons 38-44 and the
intervening intronic DNA are missing. What kind of mutation is this? - Large deletion
Tay-Sachs disease (hexosaminidase A deficiency) in 18% of Ashkenazi Jews and <1%
of non-Ashkenazi is due to a G->C at exon 12 resulting in inclusion of intron 12 in the
mRNA. What kind of mutation is this? - RNA splicing mutation
A patient has Duchenne Muscular Dystrophy (DMD) because he has two copies of
exons 41-45. What kind of mutation is this? - Large duplication
Most patients in the United States have cystic fibrosis (CF) because of the deletion of 3
base pairs resulting in the loss of a phenylalanine at codon #508. What kind of mutation
is this? - In-frame deletion
The most common mechanism by which complete Trisomy 21 arises: - Maternal meiotic
nondisjunction
What gives most accurate info on fetal aneuploidy @ 12 weeks w/out placing pregnancy
at risk? - Non-invastive prenatal testing (e.g. blood test)
If a patient has a chromosomal translocation involving homologous chromosomes, e.g.
21;21 translocation, what is risk of having offspring with unbalanced chroms? - 100%
Which chromosomal aneuploidy does NOT correlate with advancing age? - Turner
Syndrome (45,x)
What is Trisomy 13 called? - Patau syndrome
What is Trisomy 18 called? - Edwards Syndrome
A dominant pattern is typically exhibited when the normal gene product: - Functions as
a structural protein
The quickest and most accurate laboratory testing presently available to distinguish
between trisomic and translocation forms of Down syndrome or Patau syndrome is: -
Chromosomal (karyotype) analysis
What is earliest and most accurate test for FXS? - Chorionic villus sampling (9-14 wks)
WITH 100% ERIFIED QUESTIONS AND ANSWERS
Osteogenesis imperfecta type I is the mildest form of osteogenesis imperfecta because
most of the mutations that cause osteogenesis imperfecta type I: - Result in no protein
being produced from one allele (null allele)
Duchenne and Becker muscular dystrophies result from mutations in the gene for
dystrophin. The diseases differ in onset and severity, but not in inheritance pattern.
They should therefore be considered: - Allelic diseases-- this is allelic heterogeneity
Two maternal uncles with a clinical picture similar to the affected male child shows
______ inheritance - X-Linked recessive
Advanced paternal age increases risk of which mutations? - New autosomal dominant
mutations
Advanced maternal age increases risk of? - Chromosomal aneuploidy
Recurrent early pregnancy losses are often due to? - Chromosomal rearrangement
Consanguinity increase the risk of? - Autosomal recessive inheritance
What term refers to the Classic forms of single-gene inheritance - Mendelian
What term refers to the Inheritance pattern of a gene on an X or Y chromosome - Sex-
Linked
What term refers to inactivation of a gene or genes dependent upon the gender of the
transmitting parent - Imprinting
What is inheritance of extra-nuclear genetic material called? - Mitochondrial inheritance
In which kind of inheritance are parents obligate carriers? - Autosomal recessive
inheritance
What is having only one allele at a locus referred to as? - Hemizygous
A specific combination of linked alleles is called? - Haplotype
Which ethnic group most often gets alpha-thalassemia? - Asians
, Which ethnic group most often gets beta-thalassemia? - Mediterraneans
Which ethnic group most often gets Gaucher's disease? - Ashkenazic Jews
Which ethnic group most often gets PKU? - Caucasians
A patient has Duchenne Muscular Dystrophy (DMD) because exons 38-44 and the
intervening intronic DNA are missing. What kind of mutation is this? - Large deletion
Tay-Sachs disease (hexosaminidase A deficiency) in 18% of Ashkenazi Jews and <1%
of non-Ashkenazi is due to a G->C at exon 12 resulting in inclusion of intron 12 in the
mRNA. What kind of mutation is this? - RNA splicing mutation
A patient has Duchenne Muscular Dystrophy (DMD) because he has two copies of
exons 41-45. What kind of mutation is this? - Large duplication
Most patients in the United States have cystic fibrosis (CF) because of the deletion of 3
base pairs resulting in the loss of a phenylalanine at codon #508. What kind of mutation
is this? - In-frame deletion
The most common mechanism by which complete Trisomy 21 arises: - Maternal meiotic
nondisjunction
What gives most accurate info on fetal aneuploidy @ 12 weeks w/out placing pregnancy
at risk? - Non-invastive prenatal testing (e.g. blood test)
If a patient has a chromosomal translocation involving homologous chromosomes, e.g.
21;21 translocation, what is risk of having offspring with unbalanced chroms? - 100%
Which chromosomal aneuploidy does NOT correlate with advancing age? - Turner
Syndrome (45,x)
What is Trisomy 13 called? - Patau syndrome
What is Trisomy 18 called? - Edwards Syndrome
A dominant pattern is typically exhibited when the normal gene product: - Functions as
a structural protein
The quickest and most accurate laboratory testing presently available to distinguish
between trisomic and translocation forms of Down syndrome or Patau syndrome is: -
Chromosomal (karyotype) analysis
What is earliest and most accurate test for FXS? - Chorionic villus sampling (9-14 wks)
