Deck 6: Disorders of Genetics and Inheritance

Question 1

What is the likelihood that the son of a woman who is a carrier of an X-linked recessive disorder will be affected by the disorder?

A) 100%
B) 75%
C) 50%
D) 25%

Answer 1

50%

Question 2

Inversion occurs when a(n):

A) Portion of the chromosome goes missing during cell division
B) Exchange of genes occurs between three chromosomes
C) Cell with one chromosome undergoes cell division
D) Chromosome breaks and is reinserted in the wrong location

Answer 2

Chromosome breaks and is reinserted in the wrong location

Question 3

The letters p and q are used to designate what on chromosomes?

A) The central point or centromere
B) Location of specific genes
C) Number of DNA molecules in the nucleus
D) Number of chromosomes in the nucleus

Answer 3

Location of specific genes

Question 4

The term aneuploid is used to describe cells that:

A) Have the normal number of chromosomes
B) Are missing one or more chromosomes
C) Have chromosomes that are defective
D) Have twice the normal number of chromosomes

Question 5

All of the following statements characterize Down syndrome EXCEPT:

A) There is trisomy of chromosome 21.
B) Cardiac abnormalities, intussusceptions, and gastric reflux are signs.
C) There is upward slanting of the eyes and the hands and fingers are short.
D) The condition is caused by chromosomal inversion.

Question 6

In acatalasia, the body is not able to assist in the decomposition of which harmful byproduct of many normal metabolic processes?

A) Carbon dioxide
B) Uric acid
C) Hemosiderin
D) Hydrogen peroxide

Question 7

Which of the following describes a collection of signs and symptoms that occur together, and characterize a particular abnormality or condition?

A) Somatic
B) Mutant
C) Euploid
D) Syndrome

Question 8

How many copies of a gene are required for a person to be affected by an autosomal recessive disorder?

A) 1
B) 2
C) 4
D) None

Question 9

All of the following statements are true about hereditary gingival enlargement EXCEPT:

A) There is a defect in the Sh3BP2 gene.
B) The gingiva is characteristically pink, firm, and very fibrous, with little tendency to bleed.
C) The gingiva may cover the crowns of the teeth.
D) Pressure caused by the overgrowth of tissue may cause malpositioning of the teeth.

Question 10

Papillon-Lefèvre syndrome is caused by a mutation in the:

A) Son of sevenlesss-1 gene
B) IRF6 gene
C) Cathepsin C gene
D) Sh3BP2 gene

Question 11

Deoxyribonucleic acid (DNA) is located in the:

A) Mitochondria
B) Golgi complex
C) Cytoplasm
D) Nucleus

Question 12

All of the following statements are true about hypohidrotic ectodermal dysplasia EXCEPT:

A) Crowns of incisors appear tapered and conical in shape.
B) Supernumerary teeth are a prominent feature.
C) Hair is often sparse, light colored, and brittle.
D) Congenital hypodontia/oligodontia and hypoplasia of teeth are characteristics.

Question 13

Paramedian lip pits are characteristic of which of the following syndromes?

A) Nevoid basal cell carcinoma syndrome
B) Gardner syndrome
C) Van der Woude syndrome
D) Cleidocranial dysplasia

Question 14

If a gene responsible for a particular disorder is determined to have 75% penetrance, then:

A) 95% of those with the mutation will develop the disease.
B) 75% of those with the mutation will not develop the disease.
C) 75% of those with the gene will fail to express the trait.
D) 75% of those with the mutation will develop the disease.

Question 15

The normal human karyotype contains:

A) 46 pairs of chromosomes
B) 23 pairs of autosomal chromosomes and one pair of sex chromosomes
C) 22 pairs of autosomal chromosomes and one pair of sex chromosomes
D) 26 pairs of chromosomes

Question 16

All of the following statements are true about Papillon-Lefèvre syndrome EXCEPT:

A) Periodontal inflammation begins immediately after tooth eruption.
B) Aggressive oral hygiene measures control the periodontitis and prevent tooth loss.
C) Teeth may appear to be "floating in space" on radiographs.
D) The gingival tissues return to normal health after the teeth are lost or extracted.

Question 17

When an allele for a disorder is carried on a sex chromosome, it is referred to as:

A) Recessive
B) Dominant
C) X-linked or Y-linked
D) Autosomal

Question 18

How many copies of a gene are required for a person to be affected by an autosomal dominant disorder?

A) 1
B) 2
C) 4
D) None

Question 19

All of the following statements are true about mutations EXCEPT:

A) They rarely result in permanent changes in the DNA sequence that makes up a gene.
B) Acquired mutations cannot be passed on to offspring.
C) Mutations can result from exposure to teratogens.
D) They may occur before or after birth.

Question 20

Bilateral multilocular radiolucencies with distortion of the jaws, and multiple displaced and unerupted teeth are pathognomonic of:

A) Van der Woude syndrome
B) Ectodermal dysplasia
C) Cherubism
D) Edward syndrome

Question 21

The main clinical defects seen in osteogenesis imperfecta include all of the following EXCEPT:

A) Absence of sweat glands
B) Bone fragility
C) Blue sclera of eyes
D) Dentinogenesis imperfecta

Question 22

All of the following statements are true about Apert syndrome EXCEPT:

A) Pseudocleft palate formation may be observed.
B) It is not considered a true craniosynostosis.
C) Syndactyly of fingers and toes occurs.
D) It is more rare than Crouzon syndrome.

Question 23

All of the following statements are characteristic of cleidocranial dysplasia EXCEPT:

A) The head is small due to closure of skull sutures prematurely.
B) Numerous unerupted permanent and supernumerary teeth are present.
C) There is ocular hypertelorism.
D) Bone defects of the clavicle and skull are present.

Question 24

All of the following statements are true about hereditary benign intraepithelial dyskeratosis (HBID) EXCEPT:

A) Patients develop medullary carcinoma of the thyroid.
B) It shares the clinical appearance of white sponge nevus.
C) Lesions on the conjunctiva develop early in life.
D) It originated in northeastern North Carolina.

Question 25

Patients with Peutz-Jeghers syndrome need periodic evaluation for:

A) Intussusception and polyp/tumor development
B) Odontoma formation and supernumerary teeth
C) Hypogonadism, gynecomastia, and reduced fertility
D) Development of craniofacial fibrous dysplasia

Question 26

The classic radiographic appearance of fibrous dysplasia is described as:

A) Opalescent
B) Petrotic
C) Cotton ball or cotton wool
D) Ground or frosted glass

Question 27

Multiple small hamartomatous growths of the hair follicles characteristic of Multiple Hamartoma syndrome are called:

A) Melanocytic nevi
B) Basal cell carcinomas
C) Melanotic macules
D) Trichilemmomas

Question 28

McCune-Albright syndrome is characterized by all of the following EXCEPT:

A) Aplastic clavicles and frontal bossing
B) Precocious (early) puberty
C) Café-au-lait pigmentation
D) Polyostotic fibrous dysplasia

Question 29

All of the following are seen in Treacher-Collins syndrome EXCEPT:

A) Coloboma and downward slant of the palpebral fissures
B) Narrow face with hypoplasia of zygomatic bone
C) Ear defects and hearing loss
D) Hypoplastic clavicles and facial hyperplasia

Question 30

Which of the following refers to a group of syndromes that are characterized by premature closure of the cranial sutures?

A) Craniofacial hyperplasia
B) Craniofacial hypoplasia
C) Craniosynostosis
D) Prognathism

Question 31

Which of the following is NOT one of the three main types of amelogenesis imperfecta?

A) Hypoplastic
B) Hyperplastic
C) Hypocalcified
D) Hypomaturation

Question 32

Treacher-Collins syndrome involves defects:

A) Of the first and second branchial arches
B) Of the third branchial arch
C) Resulting in "cloverleaf" skull (kleeblattschädel)
D) Resulting in brachycephaly or trigonocephaly

Question 33

All of the following statements are true about the teeth in dentinogenesis imperfecta EXCEPT:

A) The overlying enamel is defective.
B) Both primary and permanent dentitions may be affected.
C) Teeth are discolored and appear dark and opalescent.
D) Dentin lacks its normal tubular structure.

Question 34

Osteopetrosis:

A) Involves a mutation in either the COLIA1 or COLIA2 gene
B) Involves a defect in bone remodeling and a decrease in bone density
C) Involves a defect in bone remodeling and an increase in bone density
D) Does not involve the jaws

Question 35

Which of the following disorders is characterized by mutations in keratin 4 and 13 genes, and thick, white, diffuse, irregular corrugated patches bilaterally on the buccal mucosa?

A) Apert syndrome
B) Gorlin syndrome
C) White sponge nevus
D) Peutz-Jeghers syndrome

Question 36

Fibrous dysplasia is:

A) Characterized by a unilocular radiolucency extending into the ramus of the mandible
B) Characterized by replacement of bone by cellular fibrous connective tissue
C) A form of Gardner syndrome
D) Associated with familial polyposis syndrome

Question 37

In which of the following syndromes do males have an extra X chromosome (XXY)?

A) Down syndrome
B) Apert syndrome
C) Nevoid basal cell carcinoma syndrome
D) Klinefelter syndrome

Question 38

Which of the following disorders is characterized by freckle-like pigmentations around the mouth and inside the oral cavity, including labial mucosa and gingiva?

A) Crouzon syndrome
B) Gorlin syndrome
C) Peutz-Jeghers syndrome
D) Down syndrome

Question 39

All of the following statements are true about amelogenesis imperfecta EXCEPT:

A) The disorder is exclusively ectodermal.
B) The clinical features are often similar to fluorosis.
C) Dentin and cementum are also improperly formed.
D) Defects occur with development and maturation of enamel matrix.

Question 40

All of the following are characteristic of nevoid basal cell carcinoma syndrome EXCEPT:

A) Epidermoid cysts of the skin
B) Multiple odontogenic keratocysts
C) Basal cell carcinomas on non-sun-exposed skin
D) Commissural lip pits

Question 41

Tooth shape in dentinogenesis imperfecta, due to bulbous crowns with cervical constriction and abnormal root formation, is described as:

A) Wedge-shaped
B) Thistle-shaped
C) Spindled
D) Rhomboidal

Question 42

Odontohypophosphatasia is a mild form of hypophosphatasia that:

A) Results in severe skeletal abnormalities
B) Only affects the teeth
C) Is characterized by mild cardiac and kidney abnormalities
D) Results in compromised immunity

Question 43

Hypophosphatasia is a rare inherited metabolic bone disorder:

A) That affects the development of both enamel and dentin
B) Characterized by excess serum and bone alkaline phosphatase activity
C) Characterized by low calcium levels in the blood
D) That affects the development of cementum and periodontal ligament

Question 44

Dentin dysplasia is characterized by all of the following EXCEPT:

A) Clinically, the crowns appear normal.
B) The "rootless teeth" appearance results from extremely short tooth roots.
C) The teeth display markedly enlarged pulp chambers.
D) Spontaneous dental abscesses or cysts may occur.