Medical Genetics: Clinical Cytogeneics

Question 1

Cri Du Chat Syndrome

Cry of the Cat

Answer 1

1. Mechanism/ Inheritance:
   Deletion, short arm of Chromosome 5
2. Findings:
   a. crying/ mewing
   b. microcephaly
   c. moderate/ severe mental retardation
3. Frequency:
   1/50,000 live births

Question 2

cytogenetics

Answer 2

the study of chromosomes, their structure, and their inheritance

Question 3

Angelman’s Syndrome

Answer 3

1. Mechanism/ Inheritance:
   deletion,
2. Findings:
   a. microcephaly
   b. seizures (severe)
   c. ataxia/ jerky movements
   d. mental retardation/ inappropriate laughter
   e. happy demeanor
3. Frequency:

Question 4

Read the following: 46, XY, t (8; 15) (p12;q23)

Answer 4

46: Chromosome Number
XY: sex chromosomes
t- type of aberration
(8;15)- implicated chromosomes
(p12; q23)- breakpoints

Question 5

Angelman’s Syndrome

Answer 5

read more

Question 6

Velcardiofacial syndrome

Answer 6

1. del 22q11.2, microdeletion

2. 
small nose, small jaw
velo- submucous/ overt cleft palate
cardio- conotruncal heart defect
facial- uniue facial features

3. 1/3000-1/5000 live births

Question 7

Technique: FISH

Answer 7

read

Question 8

Technique: microarray

Answer 8

read

Question 9

Turner Syndrome

Answer 9

1.Mechanism
Single X chromosome, Paternal non-disjunction
potential moasaicism

2. Findings
   a. short stature
   b. lymphedema
   c. gonadal dysgenesis
   d. heart disease/ renal abnormalities
3. Incidence
   1/5,000 female births

Question 10

Klinfelter Syndrome

Answer 10

1. Findings
2. Mechanism
3. Incidence

Question 11

47, XXX Females

Answer 11

1. Findings
2. Mechanism
3. Incidence

Question 12

47, XYYY Males

Answer 12

1. Findings
2. Mechanism
3. Incidence