CH6 Genetic Disorders

Question 1

Characteristic facial clinical findings include:
Bilateral cleft lip and palate
Microphthalmia or anophthalmia

Answer 1

Trisomy 13

Question 2

Trisomy 13:__% die within the first _ months of life

Answer 2

70%, 7 months

Question 3

Short stature
Webbing of the neck
Edema of the hands and feet
Low hairline on nape of neck
Broad chest with wide-spaced nipples
Abnormal aorta
Sparse body hair
Infantile external genitals
Primary amenorrhea

Answer 3

Turner Syndrome

Question 4

Not detected clinically until puberty
Taller than normal
Wide hips
Female pubic hair distribution
Development of female breasts
Intelligence levels may be lower than normal
Testes are smaller and harder
The maxilla is slightly hypoplastic

Answer 4

Klinefelter Syndrome

Question 5

Catlike cry at birth, mentally delayed

Answer 5

Cri du chat syndrome

Question 6

Cleft palate and IQ under 30

Answer 6

Wolf-Hirschhorn syndrome

Question 7

Inherited disorders affecting the gingiva and periodontium
Inherited disorders affecting the jawbones and facies
Inherited disorders affecting the oral mucosa
Inherited disorders affecting the teeth

Answer 7

Molecular Chromosomal Abnormalities

Question 8

Characterized by a cyclic decrease in the number of circulating neutrophils
Systemic manifestations include : Fever, malaise, sore throat, and occasional cutaneous infections
Kostmann syndrome or chronic neutropenia
Severe ulcerative gingivitis
Gingivostomatitis
Ulcerations on tongue and oral mucosa
Repeated episodes lead to severe periodontal disease

Answer 8

Cyclic Neutropenia

Question 9

Peripheral blood neutrophils are depressed, and the theory is that chemotaxis is depressed
Hyperkeratosis of the palms of the hands and soles of the feet
At about 1½ or 2 years of age, a gingivoperiodontal inflammatory process develops: Edema, bleeding, alveolar bone resorption, mobility of teeth
Both primary and permanent dentition are lost prematurely

Answer 9

Papillon-Lefèvre Syndrome

Question 10

Hyperkeratinization of the palms and soles and marked hyperkeratinization of labial and lingual gingiva

Answer 10

Focal Palmoplantar and Gingival Hyperkeratosis

Question 11

A component of several inherited syndromes
Composed of very firm tissue with a granular corrugated surface

Answer 11

Gingival Fibromatosis

Question 12

Gingival fibromatosis
Dysplastic or absent nails
Malformed nose and ears
Hepatosplenomegaly
Hypoplasia of terminal phalanges of fingers and toes

Answer 12

Gingival fibromatosis with multiple hyaline fibromas

Question 13

Progressive bilateral facial swelling that first appears when the patient is 1½ to 4 years of age
Ocular hypertelorism
Microscopically, bone lesions resemble central giant cell granuloma
Radiographs of the jaws reveal a characteristic “soap bubble” or multilocular appearance

Answer 13

Cherubism

Question 14

Dwarfism
Hands show polydactyly (extra digits) on the ulnar side
Fingernails and toes are hypoplastic and deformed
Fusion of the anterior portion of the maxillary gingiva to the lip from canine to canine
Missing central incisors
Presence of one centrally located abnormal tooth
Teeth have conical shape
Enamel hypoplasia
Presence of natal teeth

Answer 14

Ellis–van Creveld Syndrome (Chondroectodermal Dysplasia)

Question 15

The fontanelles remain open and the cranium develops a mushroom shape
The neck is long and narrow as a result of unilateral or bilateral hypoplasia of clavicles
The premaxilla is generally underdeveloped, resulting in pseudoprognathism
Patients have many supernumerary teeth, which are crowded in the jaws and do not erupt
Multiple cysts can develop in association with impacted teeth

Answer 15

Cleidocranial Dysplasia

Question 16

Characterized by osteomas in various bones
Osteomas of the facial skeleton will obliterate the sinuses and cause facial asymmetry
Multiple odontomas can occur in jawbones
Intestinal polyps occur that will become malignant at age 30 or later

Answer 16

Gardner Syndrome (Familial Colorectal Polyposis)

Question 17

Downward sloping of palpebral fissures
Hypoplastic nose & Hypoplastic malar bones with hypoplasia or absence of the zygomatic process
Abnormal and misplaced ears
Receding chin; Mouth appears fishlike
Patients are deaf because of a lack of otic ossicles (ear bones)
These patients have a hypoplastic mandible with flattened condyles, coronoid processes, and an obtuse mandibular angle
Teeth are malposed
Malocclusion with anterior open bite
Palate is high with a cleft in about 30% of patients

Answer 17

Mandibulofacial Dysostosis (Treacher-Collins Syndrome)

Question 18

Mutations occur that affect collagen, resulting in abnormally formed bones that fracture easily
Some individuals may only show blue sclera (that portion of the eye that is usually white)
Dentinogenesis imperfecta–like condition
Microdontia
Teeth appear opalescent or translucent but darken with age
Enamel is lost because of abnormal dentin

Answer 18

Osteogenesis Imperfecta

Question 19

Occur on the buccal aspect of the maxilla

May be single, multiple, unilateral, or bilateral

Answer 19

Maxillary Exostosis

Question 20

Cleft Lip-Palate and Congenital Lip Pits

Answer 20

(Van der Woude Syndrome)

Question 21

Multiple capillary dilations of skin and mucous membranes called telangiectasias

Lesions in mucosa of the nasal cavities may cause epistaxis

Risk of gingival hemorrhage

Answer 21

Hereditary Hemorrhagic Telangiectasia (Osler-Rendu Weber Syndrome)

Question 22

Papules and growths on facial skin, eyelids
Café au lait pigmentation
Aggravated by puberty
Mental disability
Multiple skeletal anomalies
Malignant transformation

Answer 22

Neurofibromatosis of von Recklinghausen

Question 23

White, corrugated, soft, folding buccal oral mucosa
Thick layer of keratin that desquamates and leaves a raw mucosal surface
Free gingiva is not affected

Answer 23

White Sponge Nevus (Familial White Folded Mucosal Dysplasia)

Question 24

The tooth enamel does not develop to a normal thickness

Answer 24

Type I: Hypoplastic amelogenesis imperfecta

Question 25

The tooth enamel has normal thickness but poorly calcified

Answer 25

Type II: Hypocalcified amelogenesis imperfecta

Question 26

Enamel is softer than normal
“Snowcapped”

Answer 26

Type III: Hypomaturation amelogenesis imperfecta

Question 27

Associated with taurodontic teeth

Yellow to brown pitted enamel

Enamel has a radiodensity similar to dentin

Single-rooted teeth have large pulp chambers

Answer 27

Type IV: Hypoplastic-hypomaturation amelogenesis imperfecta

Question 28

Multiple types

Associated with osteogenesis imperfecta

Hereditary opalescent dentin

No pulp chambers or root canals are seen

Roots are short and thin with periapical radiolucencies

Answer 28

Dentinogenesis Imperfecta

Question 29

Autosomal dominant

The teeth have normal crowns and abnormal roots

The teeth are generally exfoliated prematurely

Answer 29

Type I: Radicular Dentin Dysplasia

Question 30

Primary teeth are translucent with an amber color
Adult teeth appear normal

Answer 30

Type II: Coronal Dentin Dysplasia

Question 31

Hypodontia: Partial anodontia
Hypotrichosis: Decreased hair
Hypohidrosis: Decreased sweating

Answer 31

Hypohidrotic Ectodermal Dysplasia

Question 32

A decrease in serum alkaline phosphatase levels
Affects formation of bone and cementum
Teeth do not have cementum and are exfoliated prematurely

Answer 32

Hypophosphatasia

Question 33

Low serum levels of phosphorus

Large pulp chambers with very long pulp horns

Dentin has pronounced cracks, which leads to pulpal infections

Answer 33

Hypophosphatemic Vitamin D–Resistant Rickets

Question 34

An autosomal dominant inheritance pattern with variable expression
Lateral incisors may be small, peg shaped, or congenitally missing

Answer 34

Pegged or Absent Maxillary Lateral Incisors

Question 35

Large, pyramid-shaped molars with large pulp chambers
The furcation of the tooth is displaced apically

Answer 35

Taurodontism