Clincal Cytogenetics

Question 1

Cytogenetics

Answer 1

Chromosomal abnormalities that may involve the presence of extra chromosomes, loss of chromosomes, or structural alterations

Question 2

Dispermy

Answer 2

The fertilization of an ovum by two sperm cells

Question 3

Triploidy

Answer 3

Cells that contain three copies of each chromosome 69 total

Question 4

Robertsonian translocation involves the loss of

Answer 4

The short arms of the two Acrocentric chromosomes and the fusion of the long arms at the centromere

Question 5

Monopolidy

Answer 5

The loss of a chromosome set- never seen in humans

Question 6

Polyploidy

Answer 6

The gain of one of more entire chromosome sets

Question 7

Trisomy 13 is also referred to as

Answer 7

Patau syndrome

Question 8

Nondisjunction can occur in the gametes of

Answer 8

Both men and women

Question 9

What is the most common trisomy among still borns

Answer 9

Trisomy 18 Edward Syndrome

Question 10

Robertsonian translocation only involve ________ chromosomes which are:

Answer 10

Acrocentric

13, 14, 15, 21, 22

Question 11

Down Syndrome characteristics

Answer 11

Intellectual disability
Almond eyes
GI tract obstruction
Congenital heart defect
High risk for leukemia
Alzheimer’s-like symptoms later in life
Male sterility 
Hearing loss
Eye abnormalities

Question 12

Robertsonian translocation is not seen in which trisomy

Answer 12

18, Edward syndrome

Question 13

Instead of 46 XX or 46 XY *normal, a Robertsonian translocation will have

Answer 13

45 XX or 45 XY

Question 14

In a child-bearing female with Robertsonian translocation, the risk of Down Syndrome occurrence is:

Answer 14

Much higher than the risk in general population

Question 15

Small arm of chromosome

Answer 15

P

Question 16

Why are the individuals with Robertsonian translocations phenotypically normal

Answer 16

The short arms of the Acrocentric chromosomes contain redundant material (rRNA genes)

Question 17

Which tirsomy is most compatible with live birth

Answer 17

Trisomy 21

Question 18

Reciprocal translocation:

Answer 18

Chromosomal breaks on two chromosomes, the broken chromosomes exchange material resulting in derivative chromosomes

Question 19

Aneuploidy

Answer 19

The gain of one or loss of a single chromosome

Question 20

Why are abnormalities of the sex chromosomes more tolerated than abnormalities of the autosomes?

Answer 20

X-inactivation of most genes on X chromosome

Question 21

An individual who has a sex chromosome abnormality either _______ or ________ gene dosage of ______

Answer 21

Increased or decreased gene dosage of PAR1 and PAR2

Question 22

A translocation is the interchange of genetic material between:

Answer 22

Non-homologous chromosomes

Question 23

All autosomal monosomies are:

Answer 23

LETHAL

Question 24

Trisomy 18 is also referred to as

Answer 24

Edward Syndrome

Question 25

Alternate segregation

Answer 25

Two normal or two abnormal chromes in the gamete (no phenotype)

Question 26

5% of trisomy 13 is a result of

Answer 26

Robertsonian translocation

Question 27

Signs of Turner syndrome

Answer 27

Kidney abnormalities, congenital heart defects, ovarian dysgenesis, hypothyroidism, no intellectual disability but some learning disabilities

Question 28

Klinefelter syndrome:

Answer 28

47 XXY

Question 29

Symptoms of Trisomy 18 Edward syndrome

Answer 29

Death within one year
Intellectual/developmental disabilities
Diaphragmatic hernia/omaphalocele
Small eyes/mouth, receding jaw
Kidney defects
Clenched fists/overlapping fingers
Rocker-bottom feet, flexed big toe

Question 30

Trisomy 13 Patau syndrome symptoms

Answer 30

Death within a year
Holoprosencephaly *brain does not make two lobes
Postaxial polydactyly
Cleft lip/palate 
Deaf
Small eyes

Question 31

Why are autosomal trisomies 13, 18, and 21 compatible with life

Answer 31

Fewer genes on these chromosomes

Question 32

Most common sign of Klinefelter syndrome

Answer 32

Infertility

Question 33

Which autosomal trisomies are compatible with survival

Answer 33

13, 18, 21

Question 34

Monosomy for X chromosome is called

Answer 34

Turner syndrome 45, X

Question 35

XX males and XY females are errors during:

Answer 35

Recombination during the generation of gametes, SRY gene translocated

Question 36

Women under/over the age of 35 have 80% of the babies with Down syndrome?

Answer 36

Under

Question 37

Adjacent segregation

Answer 37

One normal and one abnormal chromosomes in the gamete (abnormal phenotype)

Question 38

Treatment for Turner syndrome

Answer 38

Growth hormone and estrogen therapy

Question 39

Why is Robertsonian translocation not possible in trisomy 18

Answer 39

Chromosome 18 is not Acrocentric

Question 40

The only kind of survivable monosomy:

Answer 40

X chromosome

Question 41

Nondisjunction

Answer 41

The failure of the two members of the chromosome pair to disjoin or separate during meiosis 1 or meiosis 2

Question 42

Long arm of chromosome

Answer 42

Q

Question 43

Chromosome abnormalities are the leading cause of:

Answer 43

Pregnancy loss and intellectual disability syndromes

Question 44

In Trisomy 13, 95% of cases are due to

Answer 44

Nondisjunction in the mother’s gametes

Question 45

What are the two types of translocation

Answer 45

Robertsonian

Reciprocal

Question 46

5% of trisomy 21 cases result from

Answer 46

Robertsonian translocation

Question 47

In 95% of trisomy 21 cases, the additional chromosome is contributed by:

Answer 47

The mother due to nondisjunction

Question 48

In males with 46, XX, where was the error

Answer 48

In the father of the individual, there was an aberrant recombination between the X and Y chromosomes that transferred the SRY gene to the X chromosome