Peds Genetics

Question 1

What are the 5 causes of mutations?

Answer 1

1. Multi-factorial
2. Spontaneous
3. Genetic
4. Environmental
5. Epigenetics

Question 2

What does prenatal screening consist of?

Answer 2

Maternal serum (2nd trimester)

Fetal U/S

Amniocentesis, chorionic villus sampling

Question 3

What is the purpose of prenatal screening?

Answer 3

To detect:
NTDs
Chromosomal trisomies
Cardiac defects

Question 4

What causes polyhydraminos?

Answer 4

Duodenal atresia*
Gastroschsis
Omphalocele*

Question 5

What causes oligohydraminos?

Answer 5

Renal problems (s/a Horseshoe kidney)

Question 6

What does the maternal serum screening consist of?

Answer 6

AFP
HCG
Unconjugated estriol
Inhibin A

Question 7

What do increased levels of AFP indicate?

Answer 7

Anencephaly*
Spina bifida*
Abd wall defects

Question 8

Decreased levels of AFP can indicate…

Answer 8

Trisomy 21 or 18

Question 9

What are 2 examples of a neural tube defect?

Answer 9

Spinal bifida occulta

Myelomeningocele

Question 10

What can a fetal U/S detect?

Answer 10

Nuchal thickness

Question 11

What are characteristics of Trisomy 21?

Answer 11

Hypotonia 
Down's facies 
Simian crease 
Hypoplasia of 5th digit 
Sandal toe

Question 12

What cardiac defect can you see w/ Trisomy 21?

Answer 12

AV canal (endocardial cushion defect)

Question 13

What GI effects are seen in Trisomy 21?

Answer 13

Duodenal atresia/stenosis*

Hirshsprung disease

Question 14

What endocrine disorder is seen w/ Trisomy 21?

Answer 14

Hypothyroidism

Question 15

What MSK problem is seen w/ Trisomy 21?

Answer 15

Atlantoaxial instability

Question 16

What ocular defects are seen w/ Trisomy 21?

Answer 16

Cataracts, glaucoma

Question 17

What are characteristics of Trisomy 18 (Edwards syndrome)?

Answer 17

Clenched hand w/ overlapping fingers**

Prominent occiput

Rocker-bottom feet**

Micrognathia

Umbilical hernia

Question 18

What are infant characteristics of Turners syndrome?

Answer 18

Webbed neck
Low hairline
Lymphedema*
Co-arctation of the aorta

Question 19

When do newborn screenings occur?

Answer 19

1st screen: At hospital, after 24hrs of life

2nd screen: 5-14 days

Question 20

What is phenylketonuria (PKU)?

Answer 20

Amino acid d/o, enzyme defect –> increased phenylalanine

Question 21

What are characteristics of PKU?

Answer 21

Blond hair, blue eyes
MR, autism 
Seizures
Mousy oder 
Fam hx of develop. delay

Question 22

What are characteristics of congenital hypothyroidism in a newborn?

Answer 22

Larger posterior fontanelle
Prolonged jaundice
Macroglossia
Hoarse cry 
Umbilical hernia 
Constipation

Question 23

What are characteristics of congenital hypothyroidism in childhood?

Answer 23

MR, poor growth

Question 24

What is congenital adrenal hyperplasia (CAH)?

Answer 24

Increased 17-OH hydroxylase

Question 25

What are characteristics of CAH-21 hydroxylase deficiency in males?

Answer 25

Salt wasting syndrome: - blockage of aldosterone & cortisol - hyponatremia, hypokalemia, hypoglycemia, metabolic acidosis - vomiting, shock, dehydration

Question 26

What are characteristics of CAH-21 hydroxylase deficiency in females?

Answer 26

Ambiguous genitalia virilization Salt wasting

Question 27

What are characteristics of prader-willi syndrome?

Answer 27

``` Inherited from father Deletion of 15q11-q13 Severe hypotonia, FTT Obesity, hyperphagia Small hands/feet Hypogonadism MR ```

Question 28

What are characteristics of Angelman syndrome?

Answer 28

``` Deletion of chromosome 15q-q13 happy puppet - ataxia Fair hair Seizures Uncontrollable laughter MR ```

Question 29

Describe: Branch chained amino acid defect (Leucine, isoleucine, valine)

Answer 29

Maple syrup urine disease Autosomal recessive Deficiency of decarboxylase CNS effects

Question 30

How do you dx branch chained amino acid defect?

Answer 30

Measure LIV levels

Question 31

How do you treat branch chained amino acid defect?

Answer 31

Enzyme replacement

Question 32

What is Tay Sachs disease?

Answer 32

a deficiency of hexoaminidase A

Question 33

What are characteristics of Tay-Sachs in infancy?

Answer 33

Hypotonia Blind Clumsy, awkward Seizures MC in Ashkenazi Jews and French Canadians

Question 34

What are characteristics of osteogenesis imperfecta?

Answer 34

Dominant gene defect Affects collagen MC = Type 1 (blue sclerae, brittle bones, deafness) Can be lethal (Type 2)