Cytogenetics II- Lecture 9/22/21

Question 1

Types of structural chromosomal changes (5)

Answer 1

Deletion

• Duplication
• Translocation
• Inversion
• Insertion

Question 2

Microdeletion syndromes

Answer 2

• Often submicroscopic depletion of more than one gene from chromosome
• Phenotype corresponds with number of genes lost

Question 3

Duplication 7q

Answer 3

Unusual appearance with frontal bossing, abnormal ears, hydronephrosis

Question 4

Translocations

Answer 4

Exchange of material between two or more chromosomes

Question 5

Balanced translocations

Answer 5

Even exchange, no missing materials

Can cause infertility, increased risk of unbalanced, spontaneous pregnancy loss

Question 6

Nomenclature of balanced translocation

Answer 6

Number of chromosomes, t(one to another)(breakpoint,breakpoint)

Question 7

Chance of parent with balanced translocation having unbalanced kid

Answer 7

50%

Question 8

Nomenclature unbalanced translocation

Answer 8

Number, sex chromosomes, derivative chromosome, translocation, break points

Question 9

Acrocentric chromosomes

Answer 9

13,14,15,21,22

Question 10

Robertsonian translocation

Answer 10

Two acrocentric chromosomes joining at centromere

Question 11

Robertsonian translocation nomenclature

Answer 11

45, XX/Y, Der(13;14)(q10;q10)

Question 12

digeorges disease

Answer 12

Microdeletion disorder

Question 13

PGT-A

Answer 13

Test for aneuploidy, not diagnosis though a 98% detection rate for aneuploidy

Question 14

PGT-M

Answer 14

Offered to couples at higher risk for a single gene disorder, not diagnostic

Question 15

Molar pregnancy

Answer 15

“Bunch of moles” cystic placenta

Question 16

Complete mole

Answer 16

No fetus present, diploid, two sets of paternal chromosomes only

Question 17

Partial mole

Answer 17

Fetus may be present, Diane rid triploidy (two sets of paternal chromosomes)

Question 18

Teratoma

Answer 18

Two sets of maternal chromosome, a benign tumor that may contain hair, teeth, etc

Question 19

Diagnostic testing on CVS or amniocentesis (4)

Answer 19

• FISH and karyotype
• Microarray testing
• Alpha feta protein
• Targeted testing for single gene disorders