Biochem - Stuff Missed Flashcards
Hartnup disease
results from niacin deficiency
- niacin deficiency may be due to loss of dietary tryptophan, resulting from defective intestinal and renal tubular absorption of amino acid
Niacin/Vitamin B3
synthesized from tryptophan
- tryptophan is an essential amino acid
Signs of Riboflavin deficiency
Chelosis Glossitis Keratitis, Conjunctivitis, Photophophoia Lacrimation Marked Corneal vascularization Seborrheic dermatitis
Vitamin E
- aka tocopherol
- functions as scavenger of free radicals (antioxidant)
Signs of Vitamin E deficiency
myelopathy
neurologic dysfunction
Vitamin B2 (Riboflavin)
- form FMN and FAD to form enzymes for electron transport
Pyroxidine (Vitamin B2)
coenzyme for decarboxylation and transamination of amino acids
Deficiency of Pyroxidine
Anemia
Peripheral neuropathy
Dermatitis
Phenylketonuria
inborn deficiency of phenylalanine hydroxylase to metabolize phenylalanine.
- manifests developmental delay, mental retardation, mousy body odor, and fair skin coloring
Niemann-Pick disease
- AR
- deficiency in sphingomyelinase
- progressive neurodegenerative disease
- hepatosplenomegaly
- cherry red macula
- foamy macrophages filled with spingomyelin
Fabry’s disease
- X-linked disease
- deficency in alpha-galactosidase A
- peripheral neuropathy of hands/feet
- angiokeratomas
- CV/renal disease
- accumulation of ceramide trihexosidase
Gaucher’s disease-
- Autosomal recessive
- deficiency in GLUCOcerebrocisidase
- very common
- hepatosplenomegaly
- asceptic necrosis of femur
- Bone crises
- Gaucher cells (macrophages that look like crumpled tissue paper)
Tay-Sachs disease
- Autosomal recessive
- deficient in Hexosaminidase A
- accumulation of GM2 ganglioside
- progressive neurodegeneration
- developmental delay
- cherry red spot of macula
- lysosomes with onion skin
- NO HEPATOSPLENOMEGALY (vs. Niemann-Picks disease)
Krabbe’s disease
- AR
- deficient in GALACTOcerebrocidase, leading to accumulation of galactocerebroside
- leads to peripheral neuropathy
- developmental delay
- optic atrophy
- globoid cells
Metachromatic leukodystrophy
- AR
- deficient in arylsulfatase A
- accumulation of Cerebroside sulfate
- central and peripheral demyelination with ataxia
- Dementia
Hurler’s syndrome
- deficient in alpha-L-iduronidase
- accumulation of heparan sulfat, dermatan sulfate
- presents with developmental delay,
- gargoylism (abnormal facial features)
- corneal clouding
- hepatosplenomegaly
Hunter’s syndrome
- deficient in Iduronate sulfatase
- Mild Hurler’s sndrome (no corneal clouding)
- ## mild developmental delay
Acyclovir
- monophosphorylation of viral thymidine kinase is the first step in the active conversion of acyclovir to active stae
- more effective against HSV and VZV than CMV or EBV
Pituitary adenomas
- causs symptoms from mass effect
- produce endocrine disorders
- prolactinomas are most common
- excess prolactin causes amenorrhea and galactorrhea
- bitemporal heminopsia from compression of optic chiasm is common
Interferons
- produced by eukaryotic cells in response to viral infection
- act as cytokins on neighboring cells, to stimulate neighbors to produce antivural proteins that impair viral synthesis
Edwards Syndrome
- Trisomy 18
- presents as micrognathia, low set ears, rockerbottom feet
- clenched hands with index finger overring the middle finger and fifth finger overriding fourth finger
Patau Syndrome
- Trisomy 13
- presents as holoproscephapy
- microcepthaly
- polydactly and rocker bottom feet
- multiple facial abnormalities including cleft lip/cleft palat
Most common cause of pneumonia, otitis media, and meningitis in adults
S. pneumoniae
- appears as Gram positive lancet shaped cocci in pairs
Most common cause of bacteria in adults of all ages
S. peneuomoniae
Fragile X Syndrome
- defect in FMR1 gene on long arm of chromosome Z
- increased number of CGG trinucleotide repeats leads to hypermethylation of cytosine bases and gene activation
- leads to mental retardation, facial dysmorphism, macro orchidism
Chromosomal instability disorders
- Xeroderma pigmentosum
- Ataxia-telegientascia
- Fanconi’s anemia
- Bloom syndrome
Lynch syndrome
associated with defect in DNA mismatch repair genes
- increased risk of hereditary non-polyposis cancer (HNPCC) and extraintestinal malignancies
Homocystinuria Findings
- Increased levels of homocysteine in urine
- Mental retardation
- Osteoporosis
- Tall stature
- Kyphosis
- Lens subluxation (downward and inward)
- Atherosclerosis (stroke and MI)
Homocystinuria
- autosomal recessive - comes in 3 forms:
- can result from cystathionine deficiency (tx with less MEt and increased methionine, B12 , and folate in diet)
- decreased affinity for cystathionine synthase for pyroxidase (increased B6)
- Homocysteine methyltransferase deficiency (*requires B12)
Maple syrup urine disease
- autosomal recessive
- blocked degradation of branched amino acids (Isoleucine, Leucine, Valine)
- alpha ketoacid dehydrogenase (b1)
- caused increased of serum alpha-ketoacids
- can cause severe CNS defects, mental retardation, and death
- urine smells like maple syrup
Hartnup disease
- autosomal recessive disorder
- defective neutral amino acid transporter on renal and intestinal epithelial cells
- causes tryptophan excretion in in urine and decreased absorption in gut
- can lead to pellagra
- associated with B6 deficiency
Alkaptonuria
congenital deficiency of homofentisic acid in degradative pathway of tyrosine to fumate
- autosomal recessive and benign
- Dark connective tissue, Brown pigmented sclera, black urine upon exposure to ait
- may have debilitating arthralgia ( Homocysteine not good for cartilage)
Listeria
- transmitted through contaminated food
- causes sepsis and meningitis in immunocompromised adults
- common cause of infantile meningitis
- grows well in cold temps
- gram positive but tumbling motility key feature
Aspergillosis
- neutropenic patients are at risk for Aspergillus fumigatus
- produces septate hypate with ACUTE V-shaped branching
- causes invasive aspergillosis (seen in immunosuppressed patients)
- aspergillomas (seen in TB, emphysema and sarcoid pts)
- allergic pulmonary aspergillosus (seen in asthma patients)
