Chromosomal structural abnormalities

Question 1

What is an alternative name for DiGeorge Syndrome?

Answer 1

22q11.2 deletion syndrome

Question 2

When describing gene locations what does “q” refer to?

Answer 2

the long arm of the chromosome

Question 3

Which is the largest chromosome?

Answer 3

xsome 1

Question 4

Which is the smallest chromosome?

Answer 4

xsome 22

Question 5

When describing gene locations what does “p” refer to?

Answer 5

The short arm of the chromosome

Question 6

Which chromosome is affected in diGeorge syndrome?

Answer 6

22

Question 7

Which endocrine disease is present in diGeorge syndrome?

Answer 7

Parathyroid gland is underdeveloped therefore the patient is usually hypoparathyroid and therefore hypocalcaemia

Question 8

How does diGeorge syndrome affect the immune system?

Answer 8

Reduction in mature T lymphocytes due to underdeveloped thymus gland

Question 9

Define the inheritance of diGeorge syndrome

Answer 9

22q11.2 deletion syndrome (a structural chromosomal abnormality)

Question 10

What are the features of diGeorge syndrome?

Answer 10

Autism, schizophrenia
Hypoparathyroidism (hypocalcaemia), immunodeficiency
Congential heart disease
Cleft palate

Question 11

Define the inheritance of Angelman syndrome

Answer 11

15q11.3 deletion syndrome (a structural chromosomal abnormality) - maternal inheritance

Question 12

What does 22q11.2 deletion syndrome cause?

Answer 12

DiGeorge syndrome: Autism, schizophrenia
Hypoparathyroidism (hypocalcaemia), immunodeficiency
Congential heart disease
Cleft palate

Question 13

What does 15q11.3 deletion syndrome cause?

Answer 13

Angelman syndrome

Question 14

Which chromosome is affected in Angelman syndrome?

Answer 14

15

Question 15

What are the clinical features of angelman syndrome?

Answer 15

Happy disposition, seizures, learning difficulties, macroglossia, ataxia

Question 16

Which chromosome is affected in Prader-Willi syndrome?

Answer 16

15

Question 17

Define the inheritance of angelman syndrome?

Answer 17

15q11-3 (paternal) - a chromosomal structural abnormality/imprinting disorder or maternal unilateral disomy

Question 18

What are the clinical features of Prader-Willi?

Answer 18

Obesity, hypotonia, hypogonadism, short stature

Question 19

Difference between Prader Willi and Angelman syndromes

Answer 19

Same 15q11-3 region but Prader Willi (paternal) Angelman (maternal)

Question 20

What is the long arm of a chromosome referred to as?

Answer 20

q (QOLOSSAL)

Question 21

What is the short arm of a chromosome referred to as?

Answer 21

p (petite)

Question 22

When a chromosomes best visualised?

Answer 22

During metaphase of mitsosis

Question 23

When is nuchal translucency assessed?

Answer 23

11-14 weeks gestation

Question 24

Which conditions have increased nuchal translucency?

Answer 24

Chromosomal abnormalities: Down’s, Patau, Edwards, Turners
Autosomal dominant condition: Noonan’s
Also is suggestive of cardiac defects

Question 25

What is the most common trisomy leading to miscarriage?

Answer 25

Trisomy 16 (incompatible with life)

Question 26

Which monosomy is incompatible with life?

Answer 26

All autosomal monosomies

The sex monosomy -Turner’s syndrome is the only monosomy compatible with life

Question 27

What are high levels of AFP suggestive of?

Answer 27

Neural tube defects like spina bifida

Question 28

From which gestation can CVS be performed?

Answer 28

From 11 weeks

Question 29

From which gestation can amniocentesis be performed?

Answer 29

From 15 weeks