Exam 3 Flashcards
Types of gene mutations
- Point mutations
- Insertions
- Deletions
- TNRs
With the following mutations, which require molecular analysis: a.) genome mutations, b.) chromosome mutations, c.) gene mutations
- Gene mutations require molecular analysis. Genome and chromosome mutations can be analyzed using molecular analysis, but also cytological techniques
Compare and contrast the types of DNA diagnoses
- ) Direct: when exact DNA sequence is known
a. ) Endonuclease: PCR to amplify region of interest, Digestion using appropriate endonucleases, Separation of fragments by electrophoresis
b. ) Allele-specific extension: Label DNTPs fluorescently - ) Indirect: when DNA sequence is not known, but linkage marker nearby is known (and inherited with mutated gene(s)) a.) Endonuclease, Southern Blot and probe for detection of marker
What is SKY?
- Spectral karyotyping
- Visualization of all human c/s by “painting” each pair in different fluorescent color. Used to detect rearrangements and other c/s abnormalities
What is array-based comparative genomic hybridization (array CGH)?
- Genomic DNA and a reference DNA (control) are labeled with two different fluorescent dye (one green and the other red) and hybridized to slide spotted with DNA probes spanning the human genome.
- If yellow, then equal amounts of both DNAs have hybridized
- If green or red, then amplification or deletion respectively.
Increase in methylation typically leads to what in terms of expression of a gene?
- Decreased expression, esp when methylation occurs at CpG island promoters.
Deacetylation of a gene does what to its expression?
- Associated with decrease in gene expression
A 4yo female presents with rashes on her palms and soles. Her nasal bridge looks flattened. Exam of her oral cavity shows deformed molars and incisors. Her front teeth are notched. Her shins exhibit and outward/anterior bowing. What is the most likely diagnosis?
a. ) CMV infection
b. ) Herpes infection
c. ) Rubella
d. ) Syphilis
e. ) Down syndrome
- D.) Syphilis
Top 4 congenital malformations in the US
- ) Clubfoot (25/10K)
- ) PDA (17/10K)
- ) VSD (11/10K)
- ) Cleft +/- palate (9/10K)
What is congenital atresia?
- Upper GI (esophagus) or lower GI is stenosed
What is the leading cause of mental retardation is the US?
- Down syndrome (trisomy 21)
Down syndrome.
a. ) Incidence
b. ) Karyotype
c. ) Pathogenesis
d. ) Clinical presentation
e. ) Complications
a. ) Incidence: 1/700
b. ) Karyotypes: 47 X_ (+21), 46 (14, 21q +21) = Robertsonian, 46 / 47 (+21) = Mosaic
c. ) Pathogenesis: meiotic nondisjunction, Robertsonian translocation, Mosaic type
d. ) Clinical presentation: - Mental retardation, flattened nasal bridge/facial profile, epicanthal folds, simian crease, congenital heart defects, intestinal stenosis, umbilical hernia, hypotonia, first/second toe gap
e. ) Complications: 10-20x risk of developing leukemia (AML: acute megaloblastic leukemia), almost all over 40 develop neurodegenerative changes like Alzheimers, abnormal immune response predisposition to serious infections (lung, thyroid autoimmunity)
Describe maternal age implication in higher incidence in having a baby with DS.
- Risk starts increasing at age 35.
- 40 = > 5 x increase
- 45 = > 10 x increase
Cystic Fibrosis.
a. ) Incidence
b. ) Pathogenesis
c. ) Clinical presentation
a. ) Incidence: 1/3200
b. ) Pathogenesis: AR
- Defect in CFTR (Cl channel) d/t mutation of 3 nts coding for Phe. This is most severe mutation. Other mutations are known. - Results in high salt concentration in exocrine glands and viscous luminal fluid of resp tract, GI and repro tracts (including vas deferens) - Viscous fluid in resp tract subjects lungs to recurrent infections and therefore fibrosis
c. ) Clinical presentation - First symptom noticed by parent is salty child - Recurrent pulmonary infection, cor pulmonale (right heart failure) malabsorption, obstructed vas deferens (sterility), chronic pancreatitis, secondary biliary cirrhosis, meconium ileus (in newborn)
Of the following, what are the ages associated with each:
a.) neonate, b.) infant, c.) child
a. ) neonate = 0-28 days
b. ) infant = 28 days – 1 year
c. ) child = 1-17 years old
What is considered term, preterm and post-term gestational age?
- Term = 38-42 weeks
- Preterm/premature = <37 weeks
- Post-term = >42 weeks
Describe APGAR scoring
- Scale 0-10
- A: appearance (color): 0 = entirely cyanotic, 2 = no cyanosis
- P: pulse (HR): 0 = absent, 2 = >100
- G: grimace (reflex): 0 = absent, 1 = grimace/feeble cry, 2 = sneeze / cough or pulling away
- A: activity (muscle tone): 0 = none, 1 = some flexion, 2 = active movement
- R: respiration: 0 = absent, 2 = strong
Note: 0-1 corresponds to 50% likelihood of death, 4 = ~20% likelihood of death, 7+= 0%
What is the 2nd most common cause of neonatal mortality?
- Prematurity
- What is the most common cause?
Clinical signs of prematurity besides GA
<2.5 kg, thin skin, reduced tone/activity, extremities unflexed
Complications of prematurity
- ) Hyaline membrane disease
- ) Necrotizing enterocolitis
- ) Sepsis
- ) Intraventricular hemorrhage
- ) Developmental delay
What is prematurity vs FGR (fetal growth restriction)?
- Prematurity: <37 weeks gestation
- FGR (aka SGA, IUGR) = fetal weight below the 10th percentile
Causes of FGR
- ) Fetal: chromosomal disorder, congenital malformation, infection
- ) Placental: placental anomalies, infection, confined mosaicism
- ) Maternal: preeclampsia, chronic HTN, malnutrition, renal disease, drugs, smoking How to tell difference?
- If fetal, there is symmetric FGR and all systems involved. If placental, there is asymmetric FGR and brain is spared.
Complications of FGR
- Perinatal asphyxia
- Meconium aspiration
- Hypoglycemia
- Polycythemia
- Brain dysfunction
- Hearing/visual impairment
- Learning disability
What is the most common birth injury?
- Caput succedaneum: subQ edema over presenting part of head at delivery, typically over occipitoparietal and crosses suture lines
Common birth injuries
- Caput succedaneum
- Subgaleal hematoma
- Skull fracture
- Intracranial hemorrhage
- Brachial plexus injury
- Facial nerve injury
- Fractures: clavicle, humerus
Routes of perinatal infections
- ) Transplacental: hematogenous
- ) Ascending: transcervical
- ) Combined
Most common causes of transplacental infections
- Mnemonic = TORCH
- Toxoplasmosis, other (syphilis, listeriosis, HIV, HBV, parvo B19), rubella, CMV, herpes
Congenital syphilis.
a. ) Causative agent
b. ) Clinical presentation
a. ) Causative agent: T. pallidum (spirochete)
b. ) Clinical presentation: vesiculobullous rash (pemphigus syphiliticus), mulberry molars (rounded rudimentary enamel cusps on molars), Hutchinson’s incisors (notches on biting surfaces) with widely spaced teeth, Saber shin (sharp anterior bowing of tibia)
Why is early determination of syphilis in a pregnant mother key for prevention?
- T. pallidum doesn’t cross the placenta until the 5th month of pregnancy.
Outcomes of pregnancy in syphilitic women
- 1/3rd stillbirth
- 2/3rd congenital syphilis
Congenital rubella syndrome.
a. ) Causative agent
b. ) Clinical presentation
a. ) Causative agent: Rubella virus, 1st trimester
b. ) Clinical presentation: low birth weight, purpuric rash, microcephaly, heart defects (PDA), visual problems (cataracts)
Ascending infections. Causative agents, types of infections, consequence
- Pathogens = E.coli, GBS, herpes simplex II
- Infections = chorioamnionitis, funisitis, placentitis, villitis
- Consequence = preterm birth
Neonatal sepsis. a.) Types b.) Causes c.) Risk factors
- ) Types:
a. ) Early-onset: 0-7 days
b. ) Late-onset: 8 days – 3 months - ) Causes:
a. ) Early-onset: GBS, E.Coli, Klebsiella
b. ) Late-onset: Staph, H.influenzae, Listeria, Chlamydia, Mycoplasma, Candida - ) Risk factors:
a. ) Early-onset: previous infant with GBS, GBS bacteuria during pregnancy, premature delivery, ruptured membrane > 18 h, intrapartum temp > 38 deg C
Causes of neonatal RDS (respiratory distress syndrome). What is the most common cause?
- Hyaline membrane disease (deficiency of alveolar surfactant) = most common cause
- Prematurity: prior to 28 weeks (~60% of infants)
- Head injury
- Sedation
- Aorta anomalies
- Umbilical cord coiling
- Amniotic fluid aspiration
Hyaline membrane disease
a. ) What is it?
b. ) Clinical presentation
c. ) Pathogenesis
d. ) Complications
e. ) Risk factors
a. ) What? Deficiency of alveolar surfactant
b. ) Clinical presentation: respiratory distress, cyanosis, hypoxemia, hypercapnia, metabolic acidosis. Can measure L/S (lecithin-sphingomyelin) ratio in amniotic fluid to assess for fetal lung maturity.
c. ) Pathogenesis: decreased alveolar surfactant (by type II pneumocytes) = increased surface tension = atelectasis = uneven perfusion and hypoventilation = hypoxemia and CO2 retention = acidosis = pulmonary vasoconstriction = pulmonary hypoperfusion = endothelial damage/epithelial damage = plasma leaks into alveoli = fibrin and necrotic cells (hyaline membrane) = increased diffusion gradient = vicious cycle
d. ) Complications: intraventricular hemorrhage, PDA, necrotizing enterocolitis, bronchopulmonary dysplasia, retinopathy of prematurity
e. ) Risks: preterm AGA, maternal DM, C/section, male gender
What is bronchopulmonary dysplasia (CLD: chronic lung disease)?
- Lung disease that develops in preemies born less than 32 weeks and placed on at least 4 weeks of oxygen.
- Hyperplasia and squamous metaplasia of bronchial epithelium occurs with alveolar wall thickening, peribronchial and interstitial fibrosis. This is attributed to oxygen and inflammatory cytokines that lead to reduced numbers of alveoli.
- Can lead to respiratory failure and predisposition to RSV infection – can progress to death.
Necrotizing enterocolitis.
a. ) What is it?
b. ) Clinical presentation
c. ) Pathogenesis
d. ) Complications
a. ) What? Mucosal or transmural intestinal necrosis commonly affecting the terminal ileum, less commonly colon or proximal small bowel. It is a complication of prematurity and low birth weight.
b. ) Abdominal distension, ileus and bloody stool
c. ) Controversial etiology with ischemia being a top contender. Ischemia result in focal to confluent areas of bowel necrosis.
d. ) Strictures, perforation
Fetal hydrops.
a. ) What is it?
b. ) Two types and causes?
c. ) Describe pathogenesis of immune hydrops fetalis. Describe clinical presentation of newborn.
a. ) Edema in fetus. When generalized = hydrops fetalis, when localized = cystic hygroma.
b. ) Immune hydrops (blood incompatibility) and non-immune hydrops (infections, chromosomal anomalies, twin pregnancy, CV defects)
c. ) Mother = Rh neg, Father = Rh pos. Occurs with second Rh+ pregnancy. After first pregnancy, fetus’ blood inoculates mother’s blood at delivery. Mom’s immune system becomes sensitized to fetal RBCs with Rh+ factors on cell surface and her B cells produce anti-Rh abs. At second pregnancy, mother’s antibodies cross placenta and target and destroy fetus’ RBCs. Clinical presentation = kernicterus (bilirubin-induced brain destruction), CHF, jaundice, hemolytic anemia, hepatosplenomegaly and edema.
What is SIDS? Risk factors? Autopsy findings?
- Unexplained newborn/infant death under 1 year of age.
- Risk factors:
- Maternal: young age (< 20), maternal smoking during pregnancy, drug abuse, late / no prenatal care, short intergestational intervals
- Infant: brain stem abnormality, prematurity/SGA, male, antecedent respiratory infections, multiple birth pregnancy
- Environment: prone sleep position, sleeping on soft surface, hyperthermia, postnatal passive smoking
- Autopsy findings: petechiae, lung congestion (vascular engorgement), hypoplasia of arcuate nucleaus and decreased brain stem neuronal populations
What is the most common tumor in infants?
- Hemangioma; vascular tumor
Types of hemangiomas in infants
- ) Capillary hemangiomas (strawberry, Juvenile type): skin. May grow in first few months of life, but typically spontaneously regresses leaving behind some scarring and deposits of hemosiderin pigment.
- ) Cavernous hemangiomas: cerebellum, brain stem, pancreas, liver.
Types of fibrous tumors in infants
- ) infantile myofibromatosis: most common fibrous tumor in infants, tumors in skin, muscle, bone or viscera.
- ) aggressive infantile fibromatosis: infiltrates skeletal muscle, no metastasis, but can grow very large
- ) infantile digital fibroma
- ) congenital infantile fibrosarcoma
Teratoma in infancy.
a. ) Incidence
b. ) Location
a. ) 1/20K to 1/40K live births, more common in girls
b. ) SCT (sacrococcygeal teratomas) are most common (10% of these are associated with congenital malformations).
Malignant tumors of infants/children
- Neuroblastoma
- Wilms tumor
- Rhabdomyosarcoma
Most common solid tumor in newborn. Prognosis
- Sacrococcygela teratoma (benign, 12% of them are malignant)
- Prognosis: depends on location
Most common solid congenital malignancy
- Neuroblastoma