Biochemical Flashcards
What types of metabolic disorders is hypoglycemia a sign of?
glycogen storage diseases, fatty acid oxidation disorders (others, these are main)
What is the carrier frequency of PKU?
1/58
For MSUD, what amino acids are not able to be broken down?
branched chain amino acids: leucine, isoleucine, valine
What disorder is associated with a sweaty sock odor?
isovaleric acidemia
What is the general treatment approach for urea cycle disorders?
control ammonia levels, excess calories so don’t break down protein
What are the three types of Gaucher disease?
Type 1: Non neuropathic, childhood-adult onset, no neurodegeneration (more common in AJ)
Type 2: onset before age 2, rapidly progressive and lethal by age 2-3
Type 3: lethal by age 20-30
Rare prenatal lethal type
Rare: cardiac involvement only (valvular disease)
What movement disorder is Gaucher associated with?
20-30x increased risk for Parkinson’s
What type of mutation is associated with infantile onset of Tay Sachs disease?
biallelic null alleles
What are the fasting times before symptom onset for glycogen storage diseases and fatty acid oxidation disorders?
GSD: 6-12 hours
FAO: 3-4 hours
What causes neurologic dysfunction in urea cycle disorders?
hyperammonia
What does presentation of organic acid disorders look like in the first days of life?
metabolic acidosis- early, before NBS comes back
What organs are affected by mitochondrial disorders?
organs that use a lot of oxidative phosphorylation: brain, skeletal muscle, heart, liver
What organs are affected by progressive accumulation of toxic molecules in lysosomal storage diseases?
bones, joints, liver, spleen, brain, craniofacial
What metabolic condition is said to present with a “doll-like” appearance?
GSD1
What are common symptoms for Fabry disease?
pain in extremities, sweating abnormalities, angiokeratomas, renal and cardiac issues later in life
What are common symptoms for Gaucher disease?
bone pain, spleen and liver enlargement, anemia and thrombocytopenia
What is the % enzyme activity for infantile onset Tay Sachs disease vs juvenile or adult onset?
0-5% enzyme activity vs 5-15%
What does HEXA deficiency cause?
GM2 ganglioside accumulation –> Tay Sachs disease
What percent of enzyme activity (in general) is enough to avoid symptoms of an associated biochemical disorder?
10%
What is excreted in excess in the urine of individuals with mucopolysaccharidoses?
glycosaminoglycans
What deficiency looks like methylmalonic aciduria?
vitamin B12/ cobalmin
What deficiency looks like homocystinuria?
folic acid or vitamin B12
What is a non-genetic cause of hyperammonia at birth?
neonatal asphyxia
What are signs of a urea cycle disorder in a newborn?
acute and severe hyper ammonia, tachypnea, vomiting, lethargy, normal blood pH
What are signs of an organic acidemia in a newborn?
acute sever ketoacidosis (low pH), vomiting, hyperpnea, lethargy
What are symptoms of untreated galactosemia?
liver failure, feeding issues, jaundice, sepsis, vomiting, E coli
What are signs of congenital adrenal hyperplasia in a newborn?
fasting intolerance, hypoglycemia, poor response to metabolic stress, salt wasting: low sodium high potassium, virilization in females, poor response to ACTH stimulation test
Which MPS is XL?
MPS2- Hunter
What are common symptoms of
Pompe disease?
GSD2 and LSD!
weakness, hypotonia, cardiomegaly, elevated CK, abnormal EKG, no hypoglycemia or liver involvement
What are distinct characteristics of the mito genome?
small-37 genes
no introns
circular
no homologous recombination or meiosis
continuous replication
high mutation rate
What are the varying recurrence risks for mito disease?
full sibling- 1-4% if mother not symptomatic
50% if mother symptomatic
up to 50% if offspring of affected
What are red-flag symptoms for mito disease?
stroke like lesions without vascular pattern, basal ganglia affected, encephalopathy, epilepsy, myoclonus, ataxia, cardiomyopathy, WPW, retinal degeneration, GI, liver failure, hypotonia, FTT, acidosis, exercise intolerence, anesthesia hypersensitivity
What is the most common mutation for LHON?
m.11778G>A
What does MELAS stand for?
mitochondrial encephalopathy, lactic acidosis, stroke like symptoms
What is the polymerase for the mito genome?
POLG
What metabolic disease is characterized by bony stippling?
Zellwegger spectrum
PEX1 most common gene
What skin finding is associated with Fabry disease?
angiokeratomas
What is the typical onset/timing for Leigh syndrome?
3-12 months of age, following a viral infection
What does MELAS stand for, and what is the most common causative mutation?
Mitochondrial encephalopathy, lactic acidosis, stroke like episodes
m.3243A>G MT-TL1
What is MERRF?
myoclonic epilepsy associated with ragged red fibers
90% variants in MT-TK
