Genetics Flashcards
When are genetic disorders typically diagnosed?
40-45% in the neonatal period; approximately 80% identified before 6 months of age
How common is trisomy 21?
1:500
What are typical physical findings in a child with trisomy 21?
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)
What are other conditions that commonly occur in those with trisomy 21?
Seizures Congenital heart defects (AVSD) Endocrine issues Esophageal/duodenal atresia Hearing/vision impairments Obesity Leukemia Early dementia
How common is Klinefelter’s syndrome?
1:1000 males (XXY syndrome)
What are the phenotype findings in a child with Klinefelters?
tall stature transverse crease abnormal body proportions underdeveloped secondary sex characteristics gynecomastia learning disability personality impairment
What other conditions can Klinefelter’s cause?
infertility, hypogonadism (not enough testosterone)
When does Klinefelter’s present?
at puberty—baby appears normal at birth
How common is Turner syndrome?
1:2000 females (XO karotype)
95% do not survive birth
What are typical findings in a female with Turner syndrome?
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
How common is marfan syndrome?
1:20,000
What are the most common cardiac defects found in those with marfan syndrome?
aortic regurgitation
mitral valve prolapse
aortic aneurysm
What is the typical presentation of someone with marfan syndrome?
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
What is marfan syndrome?
A connective tissue disorder affecting skeletal, cardiac, and ophthalmic body
What population is Tay-Sachs Disease most common in?
Ashkenazic Jewish population
What is the typical progression of Tay-Sachs disease?
Decreased muscle tone cherry red macula listlessness blindness deafness seizures dementia vegetative state death
How common is Tay-Sachs disease?
1:2,500
When does deterioration of Tay-Sachs typically occur?
normal at birth, deterioration begins between 3-6 months of age
What is DiGeorge (velocardiofacial) syndrome?
Congenital defect of the parathyroid glands, thymus, and conotruncal region of the heart (aorta and pulm vessels)
What is the phenotypic presentation of DiGeorge syndrome?
lateral displacement of inner canthi short palpebral fissures short philtrum (space between upper lip and nose_ micrognathia ear anomlalies
What conditions does DiGeorge lead to?
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
What condition would these characteristics typically describe: tall stature transverse crease abnormal body proportions underdeveloped secondary sex characteristics gynecomastia learning disability personality impairment
Klinefelters
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
DiGeorge
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)
Trisomy 21
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
Turner syndrome
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
Marfan syndrome
What condition would these characteristics typically describe: Decreased muscle tone cherry red macula listlessness blindness deafness seizures dementia vegetative state death
Tay-Sachs disease
