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42 Cards in this Set
- Front
- Back
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Frequency of most inborn errors of metabolism:
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rare
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3 most common inborn errors of metabolism:
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-Galactosemia
-PKU -Cystic fibrosis |
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What is the most common form of PKU?
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Type I, classic PKU
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What populations is classic PKU typically not seen in? What is it seen in?
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Not in: Blacks/Jews
Mostly in: Scandinavians |
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What enzyme is deficient in PKU?
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Phenylalanine hydroxylase
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What is the effect of high levels of plasma phenylalanine?
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Impaired brain development
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What are 3 manifestations of PKU in untreated children?
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-Seizures
-Decreased hair/skin pigment -Eczema |
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How is hyperphenylalaninemia avoided?
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By limiting Phe intake early in life.
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What patients especially need to be careful not to eat Phe?
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Women of childbearing age - the hyperphenylalaninemia is permanent despite normal neurodevelopment.
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What is a hallmark feature of PKU babies? What causes it?
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Musty/mousy odor - caused by shunt pathway metabolites excreted in sweat.
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What % loss of enzyme activity results in classic PKU symptoms?
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100%
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What % loss of enzyme activity can have minimal symptoms?
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94% (6% residual)
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What type of inheritance is seen in Galactosemia?
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Autosomal recessive
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What is the source of galactose?
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Dairy products (lactose to glucose and galactose)
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What is the enzyme deficient in Galactosemia?
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Galactose-1-phosphate uridyl transferase
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What is the result of complete lack of galactose-1-P uridyl transferase?
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Galactose1P accumulates all over the body.
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What tissues are most affected by the galactose accumulations?
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-Brain
-Eye -Liver |
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What does the liver look like in galactosemia?
-Early -Later |
Fatty at first
Like alcoholic cirrhosis later |
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What happens to the eye in galactosemia?
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Opacification/cataracts
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What are 5 major symptoms of galactosemia in infants?
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-Failure to thrive
-Vomiting -Diarrhea -Jaundice -Hepatomegaly |
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How is galactosemia managed?
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By removing galactose from the diet - don't eat dairy.
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What is the general defect that constitutes Cystic Fibrosis?
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Defective EPITHELIAL TRANSPORT resulting in abnormal fluid secretion in exocrine glands and epithelial linings.
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Does CF always show up at birth?
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No, it may not even appear until adolescence.
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What mainly causes the problems in CF patients?
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Viscous secretions clog up things
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Why is it important to know about CF?
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It is the most common lethal genetic disease affecting Caucasian populations.
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What is the inheritance pattern of CF?
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Autosomal recessive
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What do you have to be to have symptoms of CF?
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Homozygous
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Are all homozygous individuals affected equally? Why?
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No; there are many gene mutations that cause the disease.
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What gene is mutated in CF? On what chromosome?
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CFTR gene on Chr' 7q31.2
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What causes SIDS?
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Its unknown
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What usually happens in SIDS?
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The infant dies while asleep
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Why is SIDS so important?
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-Leading cause of death between 1 month and 1 year in US
-3rd leading cause of infant death overall |
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At what infant age do most SIDS deaths occur?
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Between 2mo and 4mo
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What are SIDS called in babies who survive it?
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ALTE - apparent life threatening event
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What is the most common morphologic finding in SIDS autoposies?
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Multiple petechiae
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What microscopic changes in the lungs are often seen in SIDS?
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-Vascular engorgement
-Pulmonary edema |
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What are the 3 overlapping factors in the posed "triple risk model" of SIDS?
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1. Vulnerable infant
2. Critical developmental period in homeostatic control 3. Exogenous stressor |
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What is the most compelling hypothesis for cause of SIDS?
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Delayed development of arousal and cardiorespiratory control.
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What are the critical regions in the brain for Arousal responses to hypercarbia/hypoxia/thermal stress?
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Arcuate nucleus in the VM
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What is an important maternal risk factor for SIDS?
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Smoking
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What are 3 modifiable environmental risk factors for SIDS?
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-Sleeping on tummy
-Sleeping on soft surfaces -Thermal stress |
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What is the basis for diagnosing SIDS?
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Exclusion
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