Common Chromosomal Disorders

Question 1

Inheritance of an extra copy of one chromosome results in a condition called _____.

Answer 1

trisomy

Question 2

Most commonly, trisomies occur when one pair of chromosomes fails to separate properly during meiosis, a problem termed _____.

Answer 2

nondisjunction

Question 3

The most common trisomy that results in a live birth is trisomy _____ (#).

Answer 3

21

Question 4

The most common trisomies are _____ (#), _____ (#), and _____ (#), and contain relatively few gene alleles.

Answer 4

21, 18, 13

Question 5

Trisomy of chromosomes containing more alleles is more likely to be embryo _____.

Answer 5

lethal

Question 6

The presence of extra sex chromosomes, especially the _____ chromosome, is relatively common.

Answer 6

X

Question 7

What type of congenital heart defect is most common in trisomy 21?

Answer 7

cardiac cushion defects

Question 8

Name the trisomy:

- small, strawberry-shaped head with receding chin, small jaw, and elongated occiput

Answer 8

18

Question 9

Name the trisomy:

- microcephaly, micrognathia, cleft lip

Answer 9

13

Question 10

Name the trisomy:

• epicanthal folds with upslanting palpebral fissures
• short neck with limited motion and extra skin folds
• cardiac cushion defects

Answer 10

21

Question 11

Name the trisomy:

• atrial-septal defects, ventricular-septal defects, coarctation of the aorta
• omphalocele
• esophageal atresia

Answer 11

18

Question 12

Name the trisomy:

• dextrocardia, atrial-septal defects, ventricular-septal defects, PDA
• polydactyly, syndactyly
• umbilical and inguinal hernias

Answer 12

13

Question 13

Name the trisomy:

• holoproencephaly (fusion of brain hemispheres)
• low-set ears
• deafness, vision problems
• seizures
• apnea

Answer 13

13

Question 14

Name the trisomy:

• Brushfield spots (speckling) on iris
• shorter stature than siblings
• hypothyroidism
• increased risk for leukemia

Answer 14

21

Question 15

_____ with trisomy 21 are sterile.

Answer 15

Males

Question 16

Females with trisomy 21 have a _____% chance of producing a zygote with trisomy 21.

Answer 16

50

Question 17

Of those that are not stillborn, over _____% of trisomy 18 births die within the first year.

Answer 17

90

Question 18

Of those that are not stillborn, over _____% o trisomy 13 births die within the first year.

Answer 18

90

Question 19

List the 4 syndromes of extra X chromosomes:

Answer 19

trisomy X
tetrasomy X
pentasomy X
Klinefeltier syndrom

Question 20

While _____ X is more common with normal phenotype (but usually are taller than average with slight delay in language development and a higher incidence of shyness and lack of self-confidence), _____ X and ______ X are much rarer are are consistently associated with phenotypic abnormalities.

Answer 20

1. trisomy
2. tetrasomy
3. pentasomy

Question 21

Females with _____ X are usually tall and have a greater reduction in IQ (35-70), smaller heads, and minor changes in facial features with increased incidence in skeletal abnormalities and unstable behavior.

Answer 21

tetrasomy

Question 22

Fewer than 40 females who have _____ X have been reported and have greatly reduced IQ, short stature, cleft palate, hypotonia, coarse facial features, microcephaly, hypertelorism (large distance between the eyes), and congenital heart defects.

Answer 22

pentasomy

Question 23

Men can have an extra X chromosome, resulting in a 47,XXY karyotype, also known as _____ _____.

Answer 23

Klinefelter syndrome

Question 24

The cause of _____ _____ is both maternal and paternal nondisjunction and is associated with both maternal and paternal aging with fetal survival about _____%.

Answer 24

1. Klinefelter syndrome

2. 97

Question 25

Features of _____ _____ include: declining testosterone with increased FSH by young adult age, small testes and penis, gynecomastia (50% of cases), azospermia (lack of sperm production), oligospermia, decreased libido, osteoporosis, SLE, thyroid disease, diabetes, breast CA, non-Hodgkin lymphoma, and germ cell tumors.

Answer 25

Klinefelter syndrome

Question 26

Features of having an extra _____ chromosome include taller than average, more severe teenage acne, slower motor and language development, learning disabilities, more easily distracted, hyperactive, more easily frustrated, impulsivity, disorganized and aggressive behavior.

Answer 26

Y

Question 27

Inheriting only one chromosome of a pair is a condition called _____.

Answer 27

monosomy

Question 28

The only common incidence of monosomy is _____ syndrome in which a female is missing one of the X chromosomes and has a karyotype of 45,X, along with very few cases of monosomy 21 reported.

Answer 28

Turner

Question 29

_____% of Turner syndrome individuals do not survive the first trimester.

Answer 29

99

Question 30

Name the syndrome: short stature, wide chest, disproportionally large hands and feet, congenital dislocated hip, scoliosis, kyphosis, osteoporosis, pedal edema hygroma, high/arched narrow palate, widely spaced eyes, poor dentition, wide mandible with small chin, low posterior hairline.

Answer 30

Turner

Question 31

What are possible cardiovascular problems associated with Turner syndrome?

Answer 31

1. Coarctation of the aorta 2. bicuspid aortic valve 3. aortic dissection 4. hypertension 5. coronary artery disease 6. long Q-T syndrome 7. partial anomalous pulmonary connection

Question 32

What are possible endocrine problems associated with Turner syndrome?

Answer 32

1. hypothyroidism | 2. Diabetes mellitus types 1 and 2

Question 33

What are possible renal problems associated with Turner syndrome?

Answer 33

1. collecting-system malformations 2. horseshoe-shaped kidney 3. malrotation of one or both kidneys

Question 34

What are possible eye and vision problems associated with Turner syndrome?

Answer 34

1. epicanthal folds (skinfold of upper eyelid) 2. drooping eyelids 3. uptilted palpebral fissures (opening between the upper and lower eyelids) 4. red-green color blindness 5. strabismus (misalignment of the eyes) 6. hyperopia (farsightedness)

Question 35

What are possible ear and hearing problems associated with Turner syndrome?

Answer 35

1. malformed ears 2. unusual relationship between position of eustachian tube and middle ear 3. excessively high incidence of otitis media 4. conductive hearing loss 5. progressive sensorineural hearing loss (adults) 6. cholesteatoma formation (abnormal skin growth in the middle ear behind the ear drum)

Question 36

What are possible secondary sexual features (without hormone supplementation) associated with Turner syndrome?

Answer 36

1. absent or delayed menses 2. poor breast development 3. infertility 4. ovarian dysgenesis with loss of ova and fibrotic changes 5. small, underdeveloped uterus

Question 37

_____ is the inheritance of an extra copy of each chromosome, resulting in a person who has 69 chromosomes per cell instead of 46, usually lethal, with none reaching first birthday.

Answer 37

Triploidy

Question 38

Unlike trisomy and monosomy, most partial chromosome duplications and deletions are _____ events that result from chromosomal breakage and structural rearrangement, usually during gametogenesis, not related to paternal age, with usually no reproductive capability.

Answer 38

random

Question 39

WAGR syndrome is a _____ syndrome standing for:

Answer 39

1. deletion | 2. Wilm's tumor (nephroblastoma), Aniridia (absence of the iris), Genitourinary malformations, and Retardation

Question 40

While the other features of WAGR syndrome are always present, the risk for Wilm's tumor is _____%.

Answer 40

40

Question 41

More rarely occurring, the inherited type of _____ is missing the RB gene on at least one chromosome 13 whose role is a cancer suppressor gene in preventing transcription factors from enhancing cell division.

Answer 41

retinoblastoma

Question 42

Name the deletion syndrome: microcephaly, cleft lip and palate, hypertelorism (widely spaced eyes), epicanthal folds, low-set earts with few folds, small chin, a variety of heart defects, decreased cognition.

Answer 42

Cri Du Chat

Question 43

Name the deletion syndrome: normal appearance at birth, feeding difficulties, developmental delay, slow gain of head circumference, unsteady or clumsy gait with jerky motions, frequent smiles and laughs regardless of circumstances, easily excited personality and hand waving or flapping motions, impaired speech, seizures, occipital groove, protruding tongue, large mouth with widely spaced teeth, drooling, strabismus, and lighter pigmentation than parents and siblings

Answer 43

Angelman

Question 44

Name the deletion syndrome: normal appearance at birth, narrow face, lighter pigmentation than family members, hypotonia, poor sucking reflex, failure to thrive, short stature, small hands and feet, developmental delays with reduced cognition, small gonads, insatiable appetite, behavioral problems, delayed puberty, infertility

Answer 44

Prader-Willi

Question 45

True or false: | Angelman and Prader-Willi syndromes are both a result of the deletion of chromosome 15 from q11 to q13.

Answer 45

True

Question 46

_____ syndrome is maternally derived and _____ syndrome is paternally derived from the deletion of chromosome 15 from q11 to q13.

Answer 46

1. Angelman | 2. Prader-Willi

Question 47

Genomic _____ is an epigenetic event in which a gene (or gene allele) is inactivated by means other than mutation, so the DNA sequence of the gene remains normal but its expression is inhibited.

Answer 47

imprinting

Question 48

When a gene or genes have been iprinted during gametogenesis, the effect of an imprinted gene allele from one parent means that only the nonimprinted gene allele from the other parent is _____.

Answer 48

expressed

Question 49

For the most part, when the nonimprinted gene allele is _____, its sole expression is not a problem.

Answer 49

normal

Question 50

In _____ _____ (UPD), both chromosomes of a pair come from just one parent.

Answer 50

uniparental disomy

Question 51

When a child has uniparental disomy (UPD) of chromosome 15 with both chromosomes being derived from the father, and there is no deletion of material on either chromosome, _____ syndrome results.

Answer 51

Angelman

Question 52

When a child has uniparental disomy (UPD) of chromosome 15 with both chromosomes being derived from the mother, and there is no deletion of material on either chromosome, _____ results.

Answer 52

Prader-Willi

Question 53

_____ is a condition in which two (or more) different karyotypes are consistently present in one individual.

Answer 53

Mosaicism

Question 54

_____ can be tissue-specific, meaning that some tissues can express a mixture of normal and abnormal karyotypes, and other tissues may express all or nearly all of just one type.

Answer 54

Mosaicism