Question 1

The mutation del(15)(q11q13) on the paternal chromosome results in a disease that is different from when the same mutation occurs on the maternal chromosome. This difference results from which of the following?

Accepted Answer

A)   Multifactorial inheritance
B)   Imprinting
C)   Hormonal differences
D)   Sex linkage B

Question 2

One of the rarest genome mutations, in which the affected infant has a cleft palate, abnormal heart, and developmental delays and usually does not survive beyond 6 months because of trisomy 13, is which of the following syndromes?

Accepted Answer

A)   Down's
B)   Turner's
C)   Patau's
D)   Edward's C

Question 3

Mutation in this gene product that catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate can lead to cardiovascular disease and complications in pregnancy.

Accepted Answer

A)   TP53
B)   MTHFR
C)   F5
D)   HLA-H B

Question 4

Li-Fraumeni syndrome, in which affected patients have an increased predisposition to cancer, is caused by a mutation in which of the following genes?

Accepted Answer

A)   Hemoglobin beta
B)   Dystrophin
C)   Phenylalanine hydroxylase
D)   p53 tumor suppressor gene

Question 5

Fertilization where one gamete contains an extra copy of one chromosome will result in what chromosomal abnormality?

Accepted Answer

A)   Monosomy
B)   Disomy
C)   Trisomy
D)   Tetraploidy

Question 6

Seventeen members of an extended family have a gene mutation. Only two of them have the associated phenotype. What is the term for this observation?

Accepted Answer

A)   Complete penetrance
B)   Mosaicism
C)   Autosomal dominant inheritance
D)   Incomplete penetrance

Question 7

How are transmission patterns determined?

Accepted Answer

A)   Family history
B)   Karyotyping
C)   Environmental studies
D)   Comparing unrelated individuals

Question 8

What is indicated by the term CYP2A6?

Accepted Answer

A)   Cytochrome P-450, subfamily IIA, polypeptide 6
B)   Cytochrome P-450, subfamily IIA 6
C)   Cytochrome P-450, subfamily 6, polypeptide 2A
D)   Cytochrome P-450, polypeptide A6, subfamily II

Question 9

Mitochondrial mutations primarily affect which of the following tissues?

Accepted Answer

A)   Skin
B)   Bone
C)   Muscle
D)   Lung

Question 10

A deceased family member is indicated in a pedigree by which of the following?

Accepted Answer

A)   Triangle
B)   Shaded symbol
C)   Slash through the symbol
D)   X across the symbol

Question 11

The detection of mitochondrial mutations is complicated by which of the following?

Accepted Answer

A)   Methods available for analyzing mitochondrial genes
B)   Small number of mitochondria in a cell
C)   Lack of information about the mitochondrial genome
D)   Presence of mutated and normal mitochondria in the same cell

Question 12

Which of the following syndromes is caused by deletions in mitochondrial genes as detected by Southern blot?

Accepted Answer

A)   Pearson's
B)   NARP
C)   Leber's
D)   Mitochondrial DNA depletion

Question 13

All members of a family carry the same gene polymorphism associated with a certain phenotype. There is a range of phenotypes among the family members. What is the term for this observation?

Accepted Answer

A)   Variable expressivity
B)   Complete penetrance
C)   X-linked
D)   Y-linked

Question 14

A patient is tested to determine the number of CGG repeats in the FMR1 gene by Southern blot. The patient is found to have a band that runs above the normal control band. Which of the following is the correct interpretation of these results?

Accepted Answer

A)   The patient is normal.
B)   The patient has Huntington's disease.
C)   The patient has Tay-Sachs disease.
D)   The patient has full fragile X mutation.

Question 15

Which of the following is a genetic storage disease in which sulfatides accumulate inside the lysosomes?

Accepted Answer

A)   Tay-Sachs
B)   Niemann-Pick
C)   Gaucher's
D)   Pseudo-Hurler polydystrophy

Question 16

A patient presented complaining of slurred speech and difficulty swallowing. The patient's DNA was tested to determine the number of CAG repeats in the Huntington gene by PCR. The patient had 10-29 repeats. This result is interpreted as which of the following?

Accepted Answer

A)   Normal
B)   Abnormal expansion consistent with Huntington's disease seen
C)   Patient is at risk of Huntington's disease
D)   Inconsistent results that should be repeated

Question 17

A pedigree was examined over four generations of a family with an abnormal rate of genetic disease. Scientists observed that males and females alike were affected by the disease but only when their mother was also affected. The children of affected males were all normal. All the children of affected females were affected. Which of the following describes this inheritance pattern?

Accepted Answer

A)   Mitochondrial related
B)   Autosomal dominant
C)   Autosomal recessive
D)   Sex linked

Question 18

In a pedigree, an affected female will be indicated by which of the following symbols?

Accepted Answer

A)   Open circle
B)   Shaded circle
C)   Open square
D)   Shaded square

Question 19

Almost all sex-linked disorders involve which of the following chromosomes?

Accepted Answer

A)   X
B)   Y
C)   1
D)   22

Question 20

A patient with abnormally high iron levels is tested to determine if hemochromatosis, specifically the C282Y mutation in the HFE gene, is the cause. The patient's DNA is isolated from whole blood and amplified. Amplicons are then cut with RsaI, and the resulting fragments are separated by gel electrophoresis. There are no RsaI sites in the normal 250 bp PCR product, while the C282Y mutation generates one RsaI site. The lane containing the patient's sample has three bands at 250 bp, 140 bp, and 110 bp. Controls were acceptable. Which of the following is the correct interpretation of these results?

Accepted Answer

A)   Normal
B)   Heterozygous mutation
C)   Homozygous mutation
D)   Wrong target and method performed for this disease

Exam 13: Molecular Detection of Inherited Diseases

The mutation del(15) (q11q13) on the paternal chromosome results in a disease that is different from when the same mutation occurs on the maternal chromosome. This difference results from which of the following?