Chapter 9

Question 1

Dysmorphology

Answer 1

-(dys= “painful”; morph = “shape”)
-defined as the study of congenital anomalies in the form or body parts of a person or abnormal patterns of development.

Question 2

Hypertelorism

Answer 2

Widely spaced eyes

Question 3

Ptosis

Answer 3

Drooping eyelids

Question 4

Major anamolies

Answer 4

Serious
Require medical or surgical attention
Can have life-threatening implications

Question 5

Minor anomaly

Answer 5

No serious functional or cosmetic consequences, which may or may not be surgically corrected.

Question 6

Clinodactyly

Answer 6

Laterally curved digit

Question 7

Malformation

Answer 7

-caused by a primary problem in the growth or development of a particular tissue. For example, cleft lip/palate.
-developmental problem during formation
-

Question 8

Deformation

Answer 8

-caused by the effect of a physical or mechanical force that prevents the proper growth of a structure that would have developed normally.
-embryo or fetus may be perfectly fine, but something is preventing it from growing properly.
-Constriction in the uterus is one possible cause. The correction of deformations ofren occurs after the mechanical stressor is removed. If removing the stressor does not correct the problem, clinicians start to consider the possibility that the structure was not properly formed.

Question 9

oligohydramnios

Answer 9

State of not having enough amniotic fluid

Question 10

Disruption

Answer 10

-In a disruption, a normal developmental process is “dis- rupted” by some event that leads to the destruction of normal tissue. For example, exposure ro certain drugs can cause a disruption, as can trauma or vascular insufficiency. It is different from a malformation because everything started out normally.

Question 11

Syndrome

Answer 11

a collection of features that occur together and have a consistent pattern. They are thought to have the same cause.

Question 12

Sequence

Answer 12

-one anomaly starts a chain reaction that causes another problem that then causes another and then sometimes another.
-chain of events that starts with one problem.
-One example is Pierre-Robin (pronounced “Roban”) sequence. The anomaly that starts out Pierre-Robin is micrognathia (a small jaw, which is caused by shortening and narrowing of the mandible) in the developing fetus (Fig. 9-3). Sometimes the word ret- rognathia is used to indicate that the jaw is moved posteriorly (and may be accompanied by micrognathia). This small jaw causes the tongue to be positioned backward into the pharynx (glossoptosis). The posteriorly positioned tongue can cause a cleft palate and sometimes respiratory obstruction. It is a sequence of events that started with the poorly formed jaw

Question 13

Association

Answer 13

-a collection of features occurs together, but the relationship is not clear

Question 14

Gestalt

Answer 14

Sometimes, particularly when looking at facial and developmental features, experts in clinical genetics talk about getting a sense of the whole pattern or picture of the patient. The term gestalt is used to convey this overall impression. Being able to appreciate the gestalt comes from much experience working with patients who have anomalies and with their families.

Question 15

Teratogens

Answer 15

Substances that can alter development and can cause a birth defect

Question 16

Marfan syndrome phenotype

Answer 16

long fingers and toes

Question 17

Table 9-1
Selected Named Genetic Disorders That Can Cause Cognitive Impairment and Associated Common Dysmorphic Features

Question 18

Hyperphagia

Answer 18

Excessive eating

Question 19

Midface hypoplasia

Answer 19

Central part of the face, including upper jaw, cheeks, and eye region, is small in proportion to the rest of the face

Question 20

Frontal bossing

Answer 20

Describes a very large forehead with bilateral bulging of the frontal bone prominences

Question 21

Craniofacial abnormalities

Answer 21

Variations from the usual formation of the skull and face

Question 22

Plagiocephaly

Answer 22

significant asymmetry of the skull. It can be caused by the way a newborn is positioned during sleep, which is called positional molding.

Question 23

Craniosynostosis

Answer 23

-ccurs when more than one of the cranial sutures fuse together earlier than they should. If several sutures dose toO early, the brain may not have room to grow, and intracranial pressure will increase (Reardon, 2008). This is a serious medical problem that requires urgent surgical attention.

Question 24

Macrocephaly

Answer 24

“enlarged head,” and, even though it is easy to define, exactly what makes a head seem unusually large is much less clear. The technical definition is a cranium with an occipitofrontal circumference greater than the 97th percentile compared with others of the same age and gender

Question 25

Microcephaly

Answer 25

-means that the head is smaller than expected. It is generally defined clinically as having a head circumference that is more than two standard deviations below what is expected for the child's age and gender -Microcephaly is an important finding, suggesting that the brain has grown abnormally. This may be caused by structural abnormalities or by a neurodegenerative process in the brain, or the small head circumference could just run in the family and have no consequence. Microcephaly can occur alone, with no other abnormal features, as an autosomal-recessive condition.

Question 26

syndactyly

Answer 26

(partial fusing of the digits)

Question 27

Micrognathia

Answer 27

describe the appearance of a recessed chin caused by an unusually small mandible.

Question 28

telecanthus

Answer 28

the distance between the inner canthi might be abnormally wide, but the interpupillary and outer canthi distances are within normal range. Although this situation resembles hypertelorism,

Question 29

hypotelorism

Answer 29

the eyes are much closer together than would be expected for the body size and age of the child

Question 30

palpebral fissure

Answer 30

The space between the eyelids of each eye.

Question 31

Lip pits

Answer 31

symmetrical depressions in the lip, usually in the part of the lower lip called the vermilion (the area that is somewhat redder than the skin surrounding it).

Question 32

Polydactyly

Answer 32

extra finger or toe.

Question 33

brachydactyly

Answer 33

fingers or toes are short and are not in proportion ro the rest of the body,

Question 34

syndactyly

Answer 34

-When fingers (or toes) are partially or completely fused together -It can affect only the skin and soft tissues (simple), or it can involve the bone as well (complex). Syndactyly occurs when the fingers or toes do not separate into individual digits during embryonic development.

Question 35

hypermobile or hyperexrensible

Answer 35

-joints are considered hypermobile or hyperexrensible when they have a greater range of motion than what is commonly seen at a given age. -Women are twice as likely as men to be hyperexrensible. However, hyperextensibiliry is also associated with disorders like Ehlers-Danlos syndrome and is an important assessment finding.

Question 36

SUMMARY

Answer 36

-Dysmorphology assessment is a key tool for syndrome/disorder identification by genetics professionals. Although thoroughly and accurately assessing for dysmorphic features takes lots of practice and bedside experience, nurses can use their assessment skills to screen and refer people who may have a genetic condition. This chapter provides a brief overview of important concepts in dysmorphology and some of the more frequently recognized dysmorphic features. The health-care professional not specializing in genetics must be objective and accurate in describing anatomic variations and referring concerns to those professionals with the education and experience to complete a comprehensive assessment and make an accurate diagnosis. • Dysmorphology focuses on the identification of abnormal features and their connection to genetic conditions. • Congenital anomalies can be classified as major anomalies, which usually require intervention, and minor anomalies, which usually do not require intervention. • Having one minor anomaly does not mean a person has a genetic problem. • The four causes of congenital anomalies are as follows: • Malformations, which are caused by an abnormal developmental process • Deformations, which are caused by compression from mechanical forces • Disruptions, which are caused by a disturbance in the normal developmental process • Dysplasia, which is an alteration in the size and shape and organization of cells • A syndrome is a collection of symptoms that all come from the same cause, whereas a sequence is a chain of symptoms in which each one causes the next. • Pierre-Robin is an example of a sequence that begins with micrognathia and ofren results in cleft palate and airway obstruction. • In addition to individual features, the clinician's overall impression of the patient's appearance (gestalt) is important. • Viewing the individual within the context of the family is important because some dysmorphic traits could just be benign family characteristics or could give further support for a possible genetic condition that has gone unrecognized in the family. • More than 300 genetic disorders can cause cognitive impairment. • Standard ways of measuring features have allowed clinicians to compare suspected dysmorphology against age-related norms. • Some features, such as low-set ears, are seen in many different genetic disorders as well as in people who do not have a genetic disorder. They are considered nonspecific.

Question 37

Isaac is an 8-year-old boy who has been diagnosed with Treacher Collins syndrome (TCS). which can be transmitted as either an autosomal-dominant or autosomal-recessive condition depending on the gene involved. Isaac has micrognathia (small chin and jaw). and his cheekbones and other facial bones appear underdeveloped. His eyes slant downward. and he has very small ears. His parents are most concerned about his dentition. His teeth are very crooked. Issac is bright and is doing well in school. He has one brother who shares similar facial features but has problems with snoring and significant hearing loss. The boys have two sisters who do not appear to have any facial dysmorphology. The boys' mother has slightly downslanted eyes and no other noticeable anomalies. 1. Provide an explanation for the differing phenotype among the family members described in this study. 2. Are the sisters affected or unaffected? How would you know? Is their sex a factor in whether they would be affected? 3. If TCS is being transmitted in an autosomal-dominant fashion in this family, what is the risk that another sibling would be affected? 4. Explain whyTCS is considered a syndrome and not a sequence.

Question 38

1. What term is used to describe the condition of a child who has several dysmorphic features that are related to a single known genetic cause? a. Sequence b. Disruption c. Syndrome d. Malformation

Answer 38

C

Question 39

2. Which characteristic or feature distinguishes a major anomaly from a minor anomaly? a. Major anomalies affect tissue structure, and minor anomalies affect tissue function. b. Minor anomalies affect tissue Structure, and major anomalies affect tissue function. c. Minor anomalies occur in external tissues, and major anomalies occur in internal tissues. d. Major anomalies require medical attention, whereas minor anomalies are considered a variation in structure.

Answer 39

D

Question 40

3. Which term is used to describe an anomaly caused by a physical or mechanical force that prevents the proper growth of a Structure that would have developed normally if the force was nor present? a. Dysplasia h. Disruption c. Deformation d. Malformation

Answer 40

C

Question 41

4. Which types of problems are more likely to be caused by a chromosomal abnormality? a. Single structural anomalies h. Deformations c. Syndromes d. Dysplasias

Answer 41

C

Question 42

5. How is a sequence different from a syndrome? a.A sequence is usually caused by a single gene mutation, and a syndrome is always caused by a chromosomal abnormality. b. A syndrome is usually caused by a single gene mutation, and a sequence is always caused by a chromosomal abnormality. c. In a syndrome, one structural problem leads to the development of other problems, whereas a sequence is a collection of separate but consistent anomalies. d. In a sequence, one structural problem leads to the development of other problems, whereas a syndrome is a collection of separate but consisrenr anomalies.

Answer 42

D

Question 43

6. Which statement regarding the phenotype of fetal alcohol spectrum disorder (FASD) is correct? a. Genetic and environmental factors influence the FASD phenotype. B. The malformarions in the phenotype of FASD represent a sequence. c. The genotype of FASD accurately predicts the phenotype of FASD. d. The phenotype of FASD accurately predicts the genotype of FASD.

Answer 43

A