Genetics

Question 1

When are genetic disorders typically diagnosed?

Answer 1

40-45% in the neonatal period; approximately 80% identified before 6 months of age

Question 2

How common is trisomy 21?

Answer 2

1:500

Question 3

What are typical physical findings in a child with trisomy 21?

Answer 3

microcephaly
flattened nose
hypertelorism (wide set eyes–d/t flattened nose)
Protruding tongue
Inner epicanthal folds
Upward slanting eyes
Short broad ahnds/finders/single palmar crease
Delayed growth/development
Hypotonia
Brush field spots (in eyes–white lines in iris, which are easier to see in newborns)

Question 4

What are other conditions that commonly occur in those with trisomy 21?

Answer 4

Seizures
Congenital heart defects (AVSD)
Endocrine issues
Esophageal/duodenal atresia
Hearing/vision impairments
Obesity
Leukemia
Early dementia

Question 5

How common is Klinefelter’s syndrome?

Answer 5

1:1000 males (XXY syndrome)

Question 6

What are the phenotype findings in a child with Klinefelters?

Answer 6

tall stature
transverse crease
abnormal body proportions
underdeveloped secondary sex characteristics
gynecomastia
learning disability
personality impairment

Question 7

What other conditions can Klinefelter’s cause?

Answer 7

infertility, hypogonadism (not enough testosterone)

Question 8

When does Klinefelter’s present?

Answer 8

at puberty—baby appears normal at birth

Question 9

How common is Turner syndrome?

Answer 9

1:2000 females (XO karotype)

95% do not survive birth

Question 10

What are typical findings in a female with Turner syndrome?

Answer 10

Lymphedema
Webbed neck
Low hairline
Learning disabilities
Lack of secondary sex characteristics--usually completely absent
Shield-shaped chest, with widely spaced nipples
Variety of head/neck abnormalities
Hypertension
Biscuspid aortic valve/coarc of aorta

Question 11

How common is marfan syndrome?

Answer 11

1:20,000

Question 12

What are the most common cardiac defects found in those with marfan syndrome?

Answer 12

aortic regurgitation
mitral valve prolapse
aortic aneurysm

Question 13

What is the typical presentation of someone with marfan syndrome?

Answer 13

tall stature
arm span exceeds height
thin extremities/fingers
long narrow face
pectus carinatum (pushed out) or precuts excavatum (caved in)
Hyperextension of joints
genu recurvatum (hyperextension of knee)
kyphoscoliosis
high arched, narrow palate
Cardiac defects
Ectopia lentis
Iridodonesis

Question 14

What is marfan syndrome?

Answer 14

A connective tissue disorder affecting skeletal, cardiac, and ophthalmic body

Question 15

What population is Tay-Sachs Disease most common in?

Answer 15

Ashkenazic Jewish population

Question 16

What is the typical progression of Tay-Sachs disease?

Answer 16

Decreased muscle tone
cherry red macula
listlessness
blindness
deafness
seizures
dementia
vegetative state
death

Question 17

How common is Tay-Sachs disease?

Answer 17

1:2,500

Question 18

When does deterioration of Tay-Sachs typically occur?

Answer 18

normal at birth, deterioration begins between 3-6 months of age

Question 19

What is DiGeorge (velocardiofacial) syndrome?

Answer 19

Congenital defect of the parathyroid glands, thymus, and conotruncal region of the heart (aorta and pulm vessels)

Question 20

What is the phenotypic presentation of DiGeorge syndrome?

Answer 20

lateral displacement of inner canthi
short palpebral fissures
short philtrum (space between upper lip and nose_
micrognathia
ear anomlalies

Question 21

What conditions does DiGeorge lead to?

Answer 21

increased susceptibility to infection d/t thymus aplasia
congenital heart defects (aortic arch anomalies)
hypoparathyroidism with hypocalcemia (seizures in infancy)
Cognitive/behavior psychiatric problems
Significant neonatal morbidity and mortality

Question 22

What condition would these characteristics typically describe:
tall stature
transverse crease
abnormal body proportions
underdeveloped secondary sex characteristics
gynecomastia
learning disability
personality impairment

Answer 22

Klinefelters

Question 23

What condition would these characteristics typically describe:
lateral displacement of inner canthi
short palpebral fissures
short philtrum (space between upper lip and nose_
micrognathia
ear anomlalies

Answer 23

DiGeorge

Question 24

What condition would these characteristics typically describe:
microcephaly
flattened nose
hypertelorism (wide set eyes–d/t flattened nose)
Protruding tongue
Inner epicanthal folds
Upward slanting eyes
Short broad ahnds/finders/single palmar crease
Delayed growth/development
Hypotonia
Brush field spots (in eyes–white lines in iris, which are easier to see in newborns)

Answer 24

Trisomy 21

Question 25

What condition would these characteristics typically describe:
Lymphedema
Webbed neck
Low hairline
Learning disabilities
Lack of secondary sex characteristics–usually completely absent
Shield-shaped chest, with widely spaced nipples
Variety of head/neck abnormalities
Hypertension
Biscuspid aortic valve/coarc of aorta

Answer 25

Turner syndrome

Question 26

What condition would these characteristics typically describe:
tall stature
arm span exceeds height
thin extremities/fingers
long narrow face
pectus carinatum (pushed out) or precuts excavatum (caved in)
Hyperextension of joints
genu recurvatum (hyperextension of knee)
kyphoscoliosis
high arched, narrow palate
Cardiac defects
Ectopia lentis
Iridodonesis

Answer 26

Marfan syndrome

Question 27

What condition would these characteristics typically describe:
Decreased muscle tone
cherry red macula
listlessness
blindness
deafness
seizures
dementia
vegetative state
death

Answer 27

Tay-Sachs disease