Inborn Errors of Metabolism and Nutrition Flashcards
What criteria should a genetic screening program fulfill?
- Tested disorder is prevalent and serious
- The disorder can be pre-symptomatically impacted through lifestyle changes, screening, meds or other risk-reducing interventions
- Identification of risk does not result in undue discrimination or harm
When should inborn errors of metabolism be suspected?
- Child’s symptoms accompany changes in diet
- Child’s development decreases
- Notable specific food preferences/aversions
- Fam hx of retardation or unexplained deaths in 1st and 2nd degree relatives
- Present w/sepsis like symptoms
- Recurrent hypoglycemia
- Neuro syndromes
- Unexplained acidosis
What is phenylketonuria?
- AA metabolism disorder with decreased conversion of phenylalanine to tyrosine
- Autosomal recessive
Clinical presentation of PKU in infants
- Severe mental retardation (IQ 30)
- Hyperactivity
- Seizures
- Light complexion, blond
- Eczema
What results in the best outcome of PKU in infants?
Elimination diet started in 1st month of life
Treatment of PKU
- Regulation of maternal hyperphenylalaninemia prior to conception and throughout pregnancy to prevent fetal damage
- After birth, phenylalanine deficiency diet to maintain low levels (under 6 mg/dL)
What is galactosemia?
- Autosomal recessive d/o of metabolism
- Inability to metabolize galactose
Clinical presentation of galactosemia
- Vomiting
- Jaundice
- Hepatomegaly
- Rapid onset of liver insufficiency after starting milk feeding
Treatment of galactosemia
- Avoidance of galactose for life (use soy milk)
- Calcium replacement
What is maple syrup urine disease?
- Autosomal recessive d/o of metabolism
- Deficiency of an enzyme that processes certain AAs (leucine, isoleucine, valine)
- Results in ketoaciduria
Clinical presentation of maple syrup urine disease
- Normal at birth
- 1 week later will develop feeding difficulties, coma, seizures
Treatment of maple syrup urine disease
Dietary leucine restriction
What is homocystinuria?
- Autosomal recessive d/o of metabolism
- Deficiency of CBS (enzyme)
- 50% of untreated pts are mentally retarded
Treatment of homocystinuria
- Large oral doses of pyridoxine (50% respond)
- Females must avoid OCPs (higher risk for coagulopathy)
What is nonketotic hyperglycinemia?
- Autosomal recessive d/o of metabolism
- Deficiency of glycine cleavage enzyme subunits
- Most pts will develop severe mental retardation and seizures
- Treat w/Na benzoate and dextromethorphan (or ketamine)
Define organic acidemia
- Disorders of AA and FA metabolism
- Nonamino organic acids accumulate in serum and urine
(example: maple syrup urine disease)
Example of an organic acidemia?
Maple syrup urine disease
How are fatty acid oxidation disorders treated?
Prevention of hypoglycemia (avoid prolonged fasting 8-12 hrs)
What is Smith-Lemli-Opitz syndrome?
- Autosomal recessive d/o of metabolism
- Deficiency of an enzyme
How do disorders of neurotransmitter metabolism present?
- Movement disorders
- Seizures
- Abnormal tone
- Mental retardation
Between birth and 4 months, what accounts for 40% of weight gain?
Fat
Between birth and 4 months, fat accounts for how much weight gain? How much between 24-36 months, ideally?
40% in infancy
Only 3% from 24-36 months
What are reliable indices of caloric needs in most healthy children?
Appetite and growth
What does optimal growth of an infant require?
Adequate dietary supply of protein (body does not store protein)
