Exam 2 - Metabolic disorders Flashcards
Metabolic disorders
over ___ different metabolic disorders identified
350
Metabolic disorders are often inherited as:
Autosomal recessive
Newborn screening using _____ is the most commonly used population based screening method for ___________
blood spots
metabolic disorders
Different catergories of metabolic disorders:
Carbohydrate Amino Acid Lipid Urea cycle Heavy metal transport
Amino acid disorders
Phenylketonuria
Maple syrup urine disease
Carbohydrate Disorder
Galactosemia
Urea Cycle Disorder
Ornithine transcarbamylase deficiency
Heavy Metal Transport Defects
hemochromatosis
Cystinuria
Menkes and Wilson diseases
Lipid Disorders
Smith-Lemli-Opitz syndrome
MCAD, LCHAD
Zellweger syndrome
Lysosomal Storage disorders
PKU
Phenylketonuria
PKU key clinical problems:
intellectual deficits, seizures, developmental delay, microcephaly, heart defects
PKU inheritance pattern
Autosomal recessive
Cause of PKU disease:
Lack of phenylalanine hydroxylase leads to build up of Phenylpyruvic acid
The amount of ______ and ______ eaten increases with age as the need for ____&____ increases.
no-protein medical foods
low-protein medical foods
energy and protein
What is Aspartame?
artificial sweetener
Aspartame is 50% phenylalanine
High levels of phenylalanine is _____ for a normal patient, but is especially harmful for ______
neurotoxic
PKU patients
Even in non-PKU patients, high levels of phenylalanine is harmful to ____ during _____
fetus
pregnancy
**cautious intake of this sweetener
MSUD
Maple Syrup Urine Disease
MSUD is a _______ disorder
Branched-chain amino acid
MSUD common among the _______ of Lancaster County, PA
Mennonite population
~1 in 7 is a carrier
MSUD key clinical symptoms
Poor feeding
Lethargy
Maple syrup smell
MSUD inheritance pattern
Autosomal recessive
MSUD Mutation:
mutation in the E1α geneone of 6 genes comprising the enzyme called branched-chain α -ketoacid dehydrogenase (BCKAD)
Cause of MSUD disease:
DefectiveenzymeBCKAD leads to accumulation ofBCAAs and their ketoacids, which leads to neurodegeneration and death within a few months after birth
What are the branched chain amino acids:
valine, leucine and isoleucine
BCAAS used as what:
energy sources through an oxidative pathway that uses an α -ketoacid as an intermediate.
______ of α -ketoacids is mediated by the ______ enzyme
Decarboxylation
branched-chain α -ketoacid dehydrogenase (BCKAD)
Treatment of MSUD
Dietary restriction of BCAAs. Even with treatment, episodic deterioration is common.
New Born Screening (NBS) is available to:
All infants in US shortly after birth
How is the sample collected:
Blood sample collected from heel prick
NBS screens for:
77 different genetic diseases
Samples are analyzed using:
Tandem mass spectrometry
2 step process:
1) Screening - indicates a problem MAY be present
2) Diagnostic test - confirms or dismisses whether
disease is truly present
Many _____ screening results have _____ follow-up testing
Abnormal
Normal
Causes for NBS screening to indicate abnormal results:
Blood drawn too early
Baby is premature