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PEDIATRICS EXAM REVISION > GENETICS & METABOLICS > Flashcards

GENETICS & METABOLICS Flashcards

1
Q

What lab values do you see in urea cycle defect?

A
  1. Hyperammonemia: secondary to defective protein/amino acid metabolism –> increases respiratory drive and leads to….
  2. Respiratory alkalosis: secondary to hyperventilation
  3. Elevated lactate
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2
Q

What are clinical signs and symptoms of urea cycle defect?

A

Lethargy
Poor feeding
Encephalopathy (secondary to high ammonia levels)
Intracranial hemorrhage (secondary to coagulation defects)
*** short span of time from first symptoms to irreversible brain damage

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3
Q

Emergent management of acutely unwell patient with suspected urea cycle defect?

A
  1. NPO –> stop all protein intake to reduce catabolism
  2. Reverse catabolic state: give glucose IV, hydration
  3. Call metabolics
  4. Give Arginine or Citrulline to replenish urea cycle intermediates, give carnitine, phenylacetate and sodium benzoate (provides alternate pathway for urea cycle)
  5. Monitor bloodwork closely: if ammonia >500 or q2h continues to worsen, consider ECMO or dialysis
  6. Can consider giving lactulose to remove ammonia in bowel

***Call metabolics anytime an ammonia is abnormal in an unwell child

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4
Q

What is the most likely cause of hyperammonemia in a well child with a normal gas?

A

Sampling error

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5
Q

What is the genetic basis of Prader Willi syndrome?

A

Imprinting - sporadic mutation on Chromosome 15q11

-missing paternal gene (Angelman syndrome is the equivalent)

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6
Q

What are the distinctive physical and behavioural features of Prader Willi syndrome?

A
  1. Severe obesity secondary to uncontrolled eating
  2. Downward turned, small mouth
  3. Almond shaped eyes
  4. Bitemporal narrowing
  5. Hypotonia in infancy
  6. Mild-moderate cognitive impairment
  7. Short stature - may have GH deficiency
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7
Q

What is the genetic basis for Beckwith-Wiedemann syndrome?

A

Imprinting - sporadic mutation on chromosome 11p15 -missing maternal gene OR can be due to methylation issues (Russell-Silver syndrome is the equivalent)
-leads to overactivity of IGF (insulin growth factor) gene hence the overgrowth seen clinically

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8
Q

What are the clinical features of Beckwith-Wiedemann syndrome?

A
  1. Macrosomia
  2. Ear pitting
  3. Abdominal wall defects: omphalocele
  4. Macroglossia
  5. Hypoglycemia as neonate/infant
  6. Increased risk of abdominal tumors: neuroblastoma, WIlms tumor
  7. Cardiomegaly
  8. Hemihypertrophy
  9. Normal development
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9
Q

What are the surveillance guidelines for Beckwith-Wiedemann syndrome?

A
  1. AFP q3months until 4 years old to look for hepatoblastoma
  2. AUS q3months until 8 yo
  3. Periodic CXR and urine HVA/VMA to look for neuroblastoma
  4. Screening ECHO as infant
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10
Q

What is the genetic basis of Angelman syndrome?

A

Imprinting - chromosome 15q11 (maternal gene missing)

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11
Q

What are clinical features of Angelman syndrome?

A
  1. Severe developmental delay/mental disability: can have non-verbal communication but generally, no verbal skills
  2. Temporal seizures - “laughing”, “happy puppet”
  3. Inappropriate laugher - ?brainstem defect
  4. 66% are blonde, most have pale blue eyes
  5. Microbrachycephaly
  6. Wide spaced teeth, large mouth, tongue protrusion
  7. Ataxia, jerky “puppet like” movements
  8. Hypotonia, hyperreflexia, cerebral atrophy
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12
Q

What is the genetic basis of Russell-Silver syndrome?

A

Imprinting - chromosome 11

  • equivalent is Beckwith-Wiedemann (think one is BIG and one is LITTLE)
  • one of 200 types of dwarfism
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13
Q

What are clinical features of Russell-Silver syndrome?

A
  1. Triangular face due to narrow chin
  2. Short stature - can use growth hormone replacement
  3. Immature bone age, late AF closure
  4. Clinodactyly
  5. Risk of hypoglycemia secondary to decreased substrate
  6. Diaphoresis

**can often be mistaken to have hydrocephalus because of open fontanelle and big head compared to body size

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14
Q

What are the clinical features of Noonan’s syndrome?

A

Think “male Turners” in terms of clinical features (no relation to the X chromosome though)

  1. Can be normal or have mild-moderate mental disability/learning disorders
  2. Hypertelorism
  3. Epicanthal folds
  4. Low set ears
  5. Neck webbing
  6. Ptosis
  7. Low posterior hair line
  8. Wide spaced nipples
  9. Scoliosis
  10. Risk for Arnold Chiari type 1
  11. 80% have cardiac defects: think RIGHT SIDED HEART PROBLEMS = pulmonary valve stenosis most common
  12. Cryptorchidism
  13. Mild coagulation defects
  14. At risk for leukemia/myeloproliferative disorders
  15. Short
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15
Q

What is the most common cardiac defect in Noonan’s syndrome?

A

Pulmonary valve stenosis

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16
Q

What is the genetic basis for Turner’s Syndrome?

A

45XO

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17
Q

What are the clinical features of Turner’s Syndrome?

A
  1. Prenatal cystic hygroma leads to NECK webbing once it involutes
  2. Low posterior hairline as well
  3. Low set ears
  4. Wide spaced nipples
  5. Wide carrying angle
  6. Shield chest
  7. Short stature
  8. Cardiac defects: (think LEFT sided defects) bicuspid aortic valve, coarctation of aorta
  9. Peripheral lymphedema
  10. Hypothyroidism
  11. Ovarian failure
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18
Q

What is the most common cardiac defect seen in Turner’s syndrome?

A

Coarctation of the aorta

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19
Q

What is the hallmark sign of primary carnitine deficiency?

-what laboratory findings can be seen with primary carnitine deficiency?

A

Hypoketotic hypoglycemia with prolonged fasting or concurrent illness

  • long chain fatty acid transport defect THUS cannot make ketones from fatty acid oxidation
  • lab findings: mildly elevated liver enzymes and mildly elevated ammonia
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20
Q

How do you diagnose primary carnitine deficiency?
What are the complications of primary carnitine deficiency if left untreated?
What is the treatment of primary carnitine deficiency?

A
  • Skin biopsy for fibroblast assay that assesses carnitine transport OR molecular genetic study
  • Complications: irreversible cardiomyopathy and skeletal muscle dysfunction
  • Treatment: Levocarnitine supplementation
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21
Q

What is TAR syndrome?

A

Thrombocytopenia with absent radii

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22
Q

Why is mitochondrial beta-oxidation of fatty acids so important to our survival?
-when is it particularly important?

A

Essential energy-producing pathway: particularly important during prolonged fasting or reduced caloric intake due to GI illness or increased energy usage during febrile illness

  • body switches from carbs to fat as major source of fuel
  • fatty acids are important fuels for skeletal muscle and preferred substrate for the heart
  • also used in liver and brain
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23
Q

What is the inheritance pattern of fatty-oxidation defects?

A

Autosomal recessive

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24
Q

Which 3 tissues are most affected by fatty acid oxidation defects?

A
  1. Liver
  2. Skeletal muscle
  3. Heart
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25
Q

What is the most common presentation of a fatty acid oxidation defect?
-other clinical features?

A

Hypoketotic hypoglycemia due to defective hepatic ketogenesis during prolonged periods of fasting or GI illness
-can also get chronic cardiomyopathy, muscle weakness, rhabdomyolysis

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26
Q

What is the most common fatty acid oxidation disorder?

A

MCAD (medium chain acyl CoA dehydrogenase deficiency)

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27
Q

What are the clinical features of MCAD?

-lab findings? (4)

A

Episodes of acute illness triggered by prolonged fasting

  • vomiting, lethargy rapidly progressing to coma, seizures or shock
  • lab findings:
    1. Hypoketotic hypoglycemia
    2. Normal gas (no metabolic acidosis since there are no ketones)
    3. Elevated liver enzymes and liver function tests
    4. Elevated ammonia
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28
Q

What is the acute management of acute illness in MCAD?

A
  1. Stat glucose and immediate initiation of D10W solution to treat or prevent hypoglycemia
  2. Avoid prolonged fasting
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29
Q

What clinical prognostic feature differentiates MCAD from VLAD?

A

MCAD: no cardiomyopathy or cognitive impairment

VCAD: have chronic cardiomyopathy, rhabdomyolysis
-overall, more severely affected than MCAD patients

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30
Q

What are the diagnostic tests for homocytinuria?

A
  1. Serum amino acids

2. Gold standard: enzyme assay from liver biopsy or cultured fibroblasts from skin

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31
Q

What are clinical features for homocytinuria?

A
  1. INFERIOR ectopia lantis

2. Hypercoagulability

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32
Q

A newborn baby has just been diagnosed with achondroplasia. What test should you perform before discharging the baby from hospital?

A

Polysomnography and head MRI to visualize the spinal cord in the area of the foramen magnum!

  • increased risk for central apnea secondary to arterial compression at the level of the foramen magnum
  • look also for signs of hypotonia or ankle clonus that might be suggestive of spinal cord compression
  • unexpected death can occur secondary to central apnea in 2-5% of infants with achondroplasia
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33
Q

What MSK issues do children with achondroplasia typically develop?

A
  • Cervical cord problems due to spinal stenosis

- Progressive thoracolumbar kyphosis

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34
Q

What gene is responsible for 99% of achondroplasia cases?

A

FGFR3 gene with single amino acid substitution at position 380

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35
Q

What metabolic conditions will present with significant lactic acidosis and hypoglycemia? (2)
-what about significant lactic acidosis with normoglycemia? (2)

A

Hypoglycemia:

  1. Glycogen storage type I
  2. Fructose-1,6-bisphosphatase deficiency

Normoglycemia:

  1. Mitochondrial disorders
  2. Pyruvate dehydrogenase deficiency
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36
Q

A child presents with unusual coarse facies, depressed bridge of the nose, open mouth and large tongue. His hands are spade-like, his abdomen protrudes and an umbilical hernia is present. What syndrome does he most likely have?

A

Hurler syndrome (type of mucopolysaccharidoses)

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37
Q

A patient presents with port-wine urine and photosensitzation. What condition do they most likely have?

A

Porphyria

38
Q

A patient presents with mousy urine odor. What condition do they most likely have?

A

PKU

39
Q

What are the 5 most common disorders of amino acid metabolism?

A
  1. Tyrosinemia
  2. Homocystinuria
  3. Nonketotic hyperglycemia
  4. Maple syrup urine diseas
  5. PKU
40
Q

What is the underlying cause of phenylketonuria?

  • classic vs. non-classic?
  • mode of inheritance?
  • clinical features? (6)
  • testing?
  • treatment?
A

Classic form: deficiency of phenylalanine hydroxylase enzyme (responsible for converting phenylalanine into tyrosine)

  • nonclassic form: deficiency in synthesis of biopterin which is required for adequate PAH enzyme function
  • mode of inheritance: autosomal recessive
  • clinical features:
    1. Eczema
    2. Hypopigmentation
    3. Seizures
    4. Limb spasticity
    5. Severe intellectual disability
    6. Mousy odor to urine
  • testing: measure plasma level of phenylalanine; if high, then order biopterin levels to rule out biopterin deficiency as cause of PKU
  • treatment:
    1. Phenylalanine restricted diet for life: if adherent, excellent outcome and normal intelligence
    2. Synthetic biopterin
41
Q

A mother with uncontrolled PKU delivers a baby. What clinical features is baby most likely to have?

A
  • elevated phenylalanine has teratogenic effects on fetus!!
    1. Microcephaly
    2. Growth retardation
    3. Developmental delay
    4. Congenital heart disease
42
Q

What organ is most commonly affected in tyrosinemia type I?

A

Liver

-get liver synthetic function resulting in jaundice, coagulopathy

43
Q

What are the clinical features of tyrosinemia type I?

-treatment?

A

***Think liver, kidney, CNS!
Aka Hepatorenal tyrosinemia: deficiency of FAH enzyme
-toxicity occurs due to accumulation of metabolites proximal to FAH enzyme step
-clinical features:
1. Liver failure with synthetic dysfunction: conjugated jaundice, coagulopathy, cirrhosis
2. Kidney: proximal renal tubular dysfunction leading to hypophosphatemic rickets
3. GI: failure to thrive
4. Neuro: parethesias, seizures, paralysis

Treatment: Dietary restriction of tyrosine and phenylalanine +/- liver transplant
-can also use drug NTBC to block upstream pathway of tyrosine metabolism leading to accumulation of less toxic metabolites

44
Q

What are the clinical features of tyrosinemia type II?

-treatment?

A

Aka oculocutaneous disorder: deficiency of tyrosine aminotransferase leading to accumulation of tyrosine and phenolic acids

  • clinical features:
    1. Eyes: photophobia, decreased tear production, corneal ulceration, scarring
    2. Skin: Crusted, hyperkeratotic lesions on palms and soles
    3. Neurologic: seizures, behavioural abnormalities, dev delay

Treatment: dietary restriction of tyrosine and phenylalanine

45
Q

What is the underlying cause of maple syrup urine disease?

  • clinical features
  • treatment:
A

Organic acidemia! -Deficient activity of branched-chain amino-acid alpha-ketoacid dehydrogenase (BCKD)

  • accumulation of branched chain amino acids (leucine, isoleucine, valine) = leucine is NEUROTOXIC!
  • clinical features (variable according to level of functional enzyme present):
    1. Severe forms: present in infancy with lethargy, vomiting, hypotonia, opisthotonas, seizures
    2. Intermediate enzyme levels: episodic neurologic decompensation especially during catabolic stress during intercurrent illness

***hyperammonia, metabolic acidosis with anion gap

Treatment: restriction of intake of BCAA

**name is derived from the sweet smelling urine of these patients

46
Q

What is the underlying cause of homocystinuria?

  • clinical features (5)
  • treatment?
A

Deficiency of cystathionine betasynthase

  • accumulation of homocystine since cannot be converted to cystathionine
  • pyridoxine is a cofactor for this enzyme

Clinical features:

  1. Inferior ectopia lantis (eye lens dislocation)
  2. Intellectual disability
  3. Marfanoid body habitus
  4. Osteoporosis
  5. Hypercoagulability

Treatment:

  1. 50% of patients will respond to pyridoxine supplementation
  2. Dietary restriction of methionine, addition of cystine supplements
47
Q

Which urea cycle defect disorder is the only one that is inherited in an X-linked manner?

A

(The rest are autosomal recessive in inheritance)

-OTC (ornithine transcarbamylase) deficiency is the only one that is X-linked

48
Q

What tests should be ordered to rule out urea cycle defect disorder? (3)

A
  1. Gas
  2. Ammonia level
  3. Urine organic acids
  4. Serum amino acids (will see elevation of glutamine and glycine = excess nitrogen is stored this way)
49
Q

What are the clinical features of propionic/isovaleric/methylmalonic aciduria (organic acid metabolism disorder)?

  • what tests should be ordered to diagnose an organic acid disorder? (6)
  • treatment?
A
  • **Involve metabolism of BCAA, autosomal recessive
  • Clinical features:
    1. Metabolic decompensation in neonatal period or failure to thrive and developmental delay in childhood period
    2. Peculiar body odor similar to sweaty feet
    3. Cerebral events leading to basal ganglia abnormalities
    4. Renal tubular acidosis
    5. Pancreatitis
    6. Cardiomyopathies

Tests to order:

  1. Gas: increased anion gap metabolic acidosis
  2. Urinalysis: may see ketones
  3. Hyperammonia
  4. Glucose: can be high, normal or low
  5. Acylcarnitine profile
  6. Urine organic acids

Treatment:

  1. Restrict protein intake
  2. Carnitine supplementation (provides alternate methods of propionic acid and methylmalonic acid secretion)
  3. Possible vitamin B12 supplementation (may be effective for some patients with methylmalonic aciduria)
50
Q

What are clinical features of glutaric aciduria type 1 disorder? (4)

A 
Organic acid metabolism disorder:
think NEURO!
1. Basal ganglia infarcts
2. Subdural hematomas
3. Cerebellar and frontotemporal atrophy
4. Macrocephaly
51
Q

When are patients with fatty acid oxidation defects most likely to present?

A

During prolonged fasting!!! (either intentional or secondary to intercurrent illness)

52
Q

What is the preferred energy source for the myocardium?

A

Fatty acids

53
Q

What tests should be ordered in diagnosis of fatty acid metabolism disorders? (4)

A
  1. Acylcarnitine profile
  2. Urine acylglycines
  3. Urine organic acids
  4. Serum and urine ketones (betahydroxybutarate, acetoacetate)
54
Q

What is the underlying defect in hereditary fructose intolerance?

  • clinical features?
  • treatment?
A

Deficiency of fructose 1, 6-bisphosphate aldolase

  • when patients are exposed to fructose:
    1. GI upset
    2. Seizures
    3. Coma
    4. Liver failure
    5. Renal failure
  • treatment: fructose and sucrose free diet
55
Q

What two tissues of the body are most commonly involved in glycogen storage disease?

A
  1. Muscle

2. Liver

56
Q

What are the clinical features of Pompe disease?

A

Myopathy, cardiomyopathy, hepatomegaly

-enzyme replacement therapy can extend life expectancy

57
Q

What are clinical features of Smith-Lemli-Opitz syndrome? (7)

A

SLOS = disorder of cholesterol biosynthesis

  1. Developmental delay
  2. Syndactyly of 2nd and 3rd toes
  3. Heart defects (ASD, VSD, AVSD)
  4. Kidney malformations, hypospadias
  5. Microcephaly
  6. Brain malformations: agenesis of corpus callosum
  7. GI malformations (ie. Hirschsprung)
58
Q

What clinical feature is associated with congenital disorders of glycosylation?

A

(Abnormally glycosylated proteins with multiorgan system dysfunction)
Inverted nipples!

59
Q

What are examples of peroxisomal disorders? (3)

A
  1. X linked adrenoleukodystrophy
  2. Childhood Addison disease
  3. Zellweger syndrome
60
Q

What are clinical features of Zellweger syndrome?

A

Severe disease caused by disruption of biogenesis of the entire peroxisome

  • facial dysmorphism
  • large anterior fontanelle
  • hypotonia
  • bony calcific stippling of joints
  • liver dysfunction
  • early death
61
Q

How can you differentiate between Hurler (MPS I) vs. Hunter (MPS II) syndrome?

A

Hunter syndrome does NOT have cataracts!

62
Q

You have just diagnosed one of your male patients with fragile X. His sister is performing poorly at school. What is your recommendation?

A

Order DNA testing on his sister to rule out fragile X

  • she may be a carrier
  • heterozygous female carriers: can have behavioural difficulties, cognitive impairment, developmental delay
  • DNA testing is recommended for ALL sisters of male patients with fragile X
63
Q

What is the diagnostic test for fragile X syndrome?

A

DNA testing looking for expansion of triplet DNA repeat on FMR1 gene on X chromosome

64
Q

What is the diagnostic criteria for cystic fibrosis?

A

Presence of typical clinical features OR hx of CF in a sibling OR positive newborn screening test
PLUS
Lab evidence of CFTR dysfunction: 2 elevated sweat chloride concentrations obtained on separate days OR ID of two CF mutations from each parental allele OR abnormal nasal potential difference measurement

65
Q

What is the recurrence risk for a unilateral cleft palate for subsequent pregnancies?

  • with 1 affected child?
  • with 2 affected children?
A

4% for a couple with 1 affected child

-9% with 2 affected children

66
Q

What is the underlying chromosomal abnormality in Klinefelter syndrome?

  • clinical features?
  • treatment?
A

47XXY

  1. Behavioural or psychiatric disorders
    - learning disabilities
  2. Body habitus: tall, slim and underweight with long legs (out of proportion to arms), gynecomastia, small testes/phallus for age
  3. Delayed puberty: elevated FSH and LH, low testosterone levels, elevated estradiol
  4. Increased risk of breast cancer
  5. Decreased fertility
    * ***key feature: the testes NEVER reach pubertal stage (ie. < 2.5 cm and < 4 ml) = this is why you get testosterone deficiency and infertility (no sperm production)

Treatment: testosterone replacement therapy (usually no later than 11-12 yo) to stimulate puberty (will NOT improve fertility)

67
Q

What is fetal hydantoin syndrome?

-clinical features?

A

Aka fetal dilantin syndrome = teratogenic effects of in utero exposure to phenytoin

  • clinical features:
    1. Microcephaly
    2. Hypoplasia of nails or distal phalanges
    3. Developmental delay
    4. Cardiac defects
    5. Cleft lip and palate
    6. Dysmorphic facial features: broad nasal bridge, wide fontanel, low set hairline
68
Q

What is the most likely underlying metabolic disorder in the following bloodwork:

  • hyperammonemia with acidosis
  • hyperammonemia with no acidosis or alkalosis
  • hyperammonemia with hypoglycemia
A
  • ***Hyperammonemia with:
    1. Acidosis = organic acid disorder (methylmalonic aciduria, proprionic aciduria)
    2. Alkalosis = urea cycle defect
    3. Hypoglycemia = fatty acid oxidation defect
69
Q

What are two broad etiologies of hypoketotic hypoglycemia?

A
  1. Hyperinsulinemia

2. Fatty acid oxidation defect

70
Q

What is the key lab finding in mitochondrial disorders?

A

Lactic acidosis

71
Q

Differentiate between cytogenetic testing, microarray and molecular DNA analysis.

A
  • Cytogenetic testing looks at big picture chromosome (aka like a karyotype); can diagnose down syndrome or turners for example = ex. missing or extra books in an encyclopedia collection
  • microarray is a bit more specific than cytogenetic testing, looking for deletions or duplications (like DiGeorge for example); order this if you have a dysmorphic child or heart defect = ex. missing or extra chapters in a specific encyclopedia book
  • molecular DNA analysis: looks at DNA specifically, very detailed, looks at specific mutations (like looking for specific CF gene mutations) = ex. missing or extra pages in a chapter of an encyclopedia book
72
Q

What are the 3 types of Down Syndrome?

-frequency of each?

A
  1. Nondisjunction (47XY): 95% of cases
  2. Robertsonian translocation (46XYt14;21): 4% of cases
    - this has recurrence risk
  3. Mosaicism (46XY): 1%
73
Q

What are 3 tests you need to complete within the first week of Down Syndrome kids?

A
  1. TSH/FT4
  2. ECHO
  3. Hearing test: brainstem auditory evoked potentials response +/- f/u in 3 months depending
74
Q

How often do you measure TSH in Down Syndrome children?

-what test needs to be done prior to discharging a pt home with Down Syndrome

A

At birth, 6 mo, 12 mo, yearly

-need to ECHO before sending home a Down Syndrome patient

75
Q

What are surgical issues a Down Syndrome baby may have in the newborn period? (6)

A
  1. Cardiac issues
  2. Duodenal atresia
  3. Hirschsprung’s
  4. Imperforate anus
  5. TEF
  6. Annular pancreas
76
Q

In what condition would you see hemivertebrae?

-what are important imaging tests?

A

Congenital scoliosis

  • need AUS EARLY!!!!! (to rule out visceral and GU anomalies) (unilateral renal agenesis, ureteral duplication, horseshoe kidney, genital anomalies)
  • MRI spine needed later on: spinal dysraphism, tethering of cord
77
Q

What are clinical features of Waardenberg syndrome?

-inheritance?

A

Inheritance: autosomal dominant

  • Clinical features:
    1. Heterochromic irises (different colors)
    2. Sensorineural hearing loss: NEED HEARING TEST
    3. White forelock
    4. Dystopia canthorum: makes eyes look wide apart
78
Q

A 3 mo old is suspected of having an inborn error of metabolism and has neurological and cardiac involvement. What can you give before a definitive diagnosis is made to prevent further sequelae? (2)

A
  1. Thiamine

2. Carnitine

79
Q

A patient presents with split uvula. What do you need to check for?

A

Submucosal cleft palate! Stick your fingers in their mouth and feel because this can lead to speech problems and feeding problems

80
Q

What are examples of diseases that are autosomal dominant?

A
  1. NF-1
  2. Achondroplasia
  3. Myotonic dystrophy
  4. Hereditary angioedema
81
Q

What two conditions cause positive urine reducing substances?

A
  1. Galactosemia

2. Hereditary fructose intolerance

82
Q

What are clinical features of Gaucher disease?

A

B-glucocerebrosidase deficiency = abnormal accumulation of glucocerebroside in reticuloendothelial system

  1. Bone marrow infiltration with glucocerebroside = pancytopenia
  2. HSM
  3. Erlenmeyer flash appearance of long bones
    - dx: biopsy skin/liver and see absence of glucocerebroside activity
83
Q

What is the most common cause of congenital hypothyroidism?

A

Thyroid dysgenesis

84
Q

What are the clinical features of Jeune syndrome?

A

Asphyxiating thoracic dystrophy = short stature, long and narrow thorax, hypoplastic lungs, liver fibrosis, short limbs

85
Q

What are the clinical features of Crouzon syndrome?

A
  1. Craniosynosthosis (usually coronal)
  2. Proptosis
  3. Brachycephaly
  4. Hypertelorism
  5. Strabismus
  6. Beak nose
  7. Midface hypoplasia
  8. High arch palate
86
Q

In patients with retinoblastoma, what is their chance of developing a secondary primary tumor and which one is it?

A

Retinoblastoma = 15-90% develop osteosarcoma!

87
Q

A newborn baby has low sloping shoulders, right hand attached at the elbow with agenesis of the forearm, cardiac abnormalities, missing chest wall musculature and a bifid thumb. What is your most likely diagnosis?

A

Holt Oram syndrome
-abnormalities in the upper extremities, hypoplastic radii, thumb abnormalities, cardiac anomalies, occasionally missing pectorals major muscle

88
Q

What are 3 conditions that involve expansion of a trinucleotide repeat?

A
  1. Fragile X
  2. Friedreich Ataxia
  3. Myotonic dystrophy
89
Q

You do a quad screen and find decreased estriol, AFP and increased HCG. What is the likely diagnosis?

A

Down Syndrome

90
Q

You do a quad screen and find decreased AFP, estriol, and HCG. What is the likely diagnosis?

A

Trisomy 18

91
Q

Compare and contrast amniocentesis and CVS:

  • timing of test?
  • risk of pregnancy loss?
A

Amniocentesis:

  • done at 15-18 weeks
  • lower risk of pregnancy loss (0.1%)

CVS: done at 12-15 weeks
-higher risk of pregnancy loss (1%)

92
Q

What is the underlying genetic abnormality in Cri Du Chat syndrome?

A

Deletion of short arm of chromosome 5 = get cat like cry from tracheal hypoplasia, low birth weight, postnatal failure to thrive, craniofacial abnormalities

PEDIATRICS EXAM REVISION (56 decks)

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