Buzz Phrases Flashcards
Anterior neuropore fusion defects
Anencephaly, encephalocele
Posterior neuropore fusion defects
Myelomeningocele, spina bifida
Signals for neural tube differentiation
From the mesoderm of notochord: sonic hedgehog; from lateral epidermal ectoderm: bone morphogenic proteins
Risk factors for neural tube defects
Folate deficiency, AEDs, maternal diabetes, vitamin A toxicity, females
Cells of origin of CNS
Ectoderm, derived from neural tube
Cells of origin of peripheral nervous system
Ectoderm, derived from neural crest cells
Cells of origin of vertebral bodies
Mesoderm of notochord
Balloon cells
Focal cortical dysplasia, disorder of cell proliferation
Holoprosencephaly
Failure of prosencephalon to divide into cerebral hemisphere and other structures. Problem during 4-8 weeks GA
Reduced visual acuity, panhypopit, absent septum pellucidum
Septo optic dysplasia
Smooth brain, small chin, thin upper lip, intractable epilepsy. Disorder and genetics?
Lissencephaly type I, Miller-Dieker syndrome, LIS1 gene, chromosome 17, disorder of microtubules and dynein
Gene mutation leads to smooth brain in males, double cortex in females. Dx? Gene?
X-linked lissencephaly, DCX gene (doublecortin protein)
Three disorders associated with cobblestone cortical malformation
Walker-Warburg syndrome, Fukuyama muscular dystrophy, and muscle-eye-brain disease.
Molar tooth sign
Joubert syndrome and other disorders of cerebellar hypoplasia
Childhood obesity and intellectual disability
Prader-Willi syndrome, Laurence-Moon syndrome
Inappropriate laughter, arm flapping, intellectual disability, seizures, prominent jaw
Angelman’s syndrome
What’s the genetic defect in Prader-willi and Angelman syndrome?
Chromosome 15q11-13
Paternally inherited—> Prader Willi
Maternally inherited —> ANGELman’s
Intellectual disability, big ears and testes - disorder and genetic defect?
Fragile X, CGG repeat (Child w/ Giant Gonads)
Developmental regression at 6-18 months, hand wringing and microcephalic in a female
Rett syndrome, MECP2 mutation, CDKL5 mutation also results in Rett-like syndrome with earlier onset sz
Cafe au lait macules
NF1
Shagreen patch
TSC
Cutaneous neurofibromas
NF1
Gene in NF2
Merlin gene, chromosome 22
Gene in NF1
Neurofibromin gene, chromosome 17
Axillary or inguinal freckling
NF1
Bilateral vestibular schwannomas
NF2
Lisch nodules- what are they
Iris hamartomas, seen in NF1
Name some features of TSC
SEGAs, shagreen patch, ash leaf spots, dental enamel pits, lymphangiomatosis (females), cardiac rhabdomyomas, angiolipomas of kidney
Sphenoid wing dysplasia
NF1
Multiple intracranial AVMs
HHT (aka Osler Weber Rendu syndrome)
Tx to inhibit growth of TSC hamartomas
Rapamycin (mTORi)
Hypopigmented streaks that follow skin lines
Hypomelanosis of Ito, seen in neurocutaneous syndrome assoc with sz and dev delay
Hyperpigmented cutaneous lesions and leptomeningeal melanoma
Neurocutaneous Melanosis
Hemifacial atrophy
Parry-Romberg syndrome
Megalencephaly, symmetric white matter disease involving U fibers, N-acetylaspartic peak on MRS. disease and enzyme def?
Canavan’s disease
Aspartoacylase deficiency
Symmetric white matter involvement in primarily posterior regions, spares U fibers
Adrenoleukodystrophy
Angiokeratomas, renal failure, hypertension, strokes, autonomic dysfunction. Disease and enzyme?
Fabry’s disease
(Funky autonomics, Angiokeratomas, BP, Renal fail, Y Strokes)
X linked
A-galactosidase deficiency (alpha gal)
Buildup of glycosphingolipids in lysosomes
Metachromatic leukodystrophy enzyme
Arylsulfatase A deficiency
Disorder of cholesterol trafficking in intracellular domain
Niemann Pick type C
C for cholesterol!
Acid sphingomyelinase deficiency
Niemann Pick types A and B
Hexoaminidase A and B deficiency
Sandoff’s disease
Hexoaminidase A deficiency
Tay Sachs disease
Globoid cells
Krabbe disease
Galactocerebroside B galactosidase deficiency
Gaucher’s disease
Glucocerebrosidase deficiency
Wrinkled tissue paper cells : gaucher cells
disorders of cell proliferation (name 3)
- megalencephaly
- microcephaly
- focal cortical dysplasia
disorders of neuronal migration (name 3)
- lissencephaly (agyria, pachygyria, subcortical band heterotopia)
- cobblestone complex malformations
- all types of heterotopia
disorders of cortical organization (name 3)
- polymicrogyria
- schizencephaly
- FCD with normal cell types
also microdysgenesis
hemifacial atrophy, headaches, seizures, hemiparesis
Parry-Romberg syndrome
congenital skin lesions + leptomeningeal melanosis. risk of hydrocephalus and melanoma
neurocutaneous melanosis
X-linked disorder that causes hyperpigmented lesions following skin lines in girls, ID, ocular problems. dx and gene?
incontinentia pigmenti (lethal in boys)
NEMO mutation
hypopigmented skin lesions that follow skin lines, eye problems, ID, seizures
hypomelanosis of Ito
enchondromas (cartilage tumors) + secondary hemangiomas, CNS tumors and skin findings
Maffucci’s syndrome
cafe au lait spots, axillary freckling, dysmorphic face. NO optic glioma, neurofibromas, or Lisch nodules. Dx?
Legius’ syndrome, AD, SPRED1 gene on chromosome 15. no increased cancer risk like NF1
dx criteria for NF1
2 or more:
1) 6+ cafe au lait macules
2) inguinal/axillary freckling
3) 2+ cutaneous neurofibromas or 1 plexiform
4) 2+ Lisch nodules
5) optic pathway glioma
6) bony lesion
7) 1st degree relative with NF1
inheritance pattern of cobblestone malformations
autosomal recessive
ex. Walker Warburg, Fukuyama, muscle eye brain
patient with ectopia lentis, marfanoid habitus, stroke risk, intellectual disability. dx? Deficiency? Inheritance? Labs? Tx?
homocysteinuria
caused by cystathionine-B-synthase deficiency
AR mutation in gene CBS on chromo 21
increased homocystine, homocysteine and methionine in blood and urine
tx: pyridoxine can help in one variant + low protein diet , folate and B12
periventricular nodular heterotopia genetics
in more than 50% of cases, X-linked dominant, affecting heterozygous females because boys die young, more severe presentation
FLNA gene (FILAMIN A) on X chromosome
urea cycle disorders (clinical features, lab findings, inheritance?)
triad of hyperammonemia, encephalopathy, respiratory alkalosis. cerebral edema. most present in newborn period except arginase deficiency
patients will have very high serum ammonia, no evidence of organic acidemia, normal anion gap, and normal serum glucose
most common is ornithine transcarbylase deficiency (OTC deficiency) which is X-linked recessive, but all others are AR
excessive abnormal gyri that are small and separated by shallow gyri
polymicrogyria
most common location of polymicrogyria
perisylvian
deep cleft that extends from pial surface to the ventricle and is lined with cortex (gray matter)
schizencephaly
closed lip vs open lip schizencephaly
closed - cerebral cortical walls on either side of cleft are intact.
open - two walls are separated by csf
porencephaly vs schizencephaly
porencephalic cysts lined with white matter, whereas schiz is gray matter.
porencephaly = CSF filled cysts resulting from in utero infarction or other insult. not a cortical malformation
floppy baby that can’t feed well and needs a GT, later hyperphagia in childhood
prader willi syndrome
15q11-13, paternally inherited
happy puppet syndrome: inappropriate laughter, ataxic, intractable epilepsy, microcephaly, ID, prominent jaw
angelman syndrome
15q11-13, maternally inherited
williams syndrome genetic deletion
chromosome 7q
cri du chat genetics
chromosome 5p deletion
enzyme that is deficient in methylmalonic acidemia and what products build up?
methylmalonyl-CoA mutase
which catalizes
L methylmalonyl CoA —-> succinyl CoA, which then enters Krebs cycle
leads up build up of propionyl-CoA, propionic acid, methylmalonic acid –> metabolic acidosis, hyperglycinemia, hyperammonemia
cofactor required for the methylmalonic acid equation
5’-deoxyadenosylcobalamin
newborn with metabolic acidosis, ketosis, hyperglycinemia, hyperammonemia
treatment?
methylmalonic acidemia
tx: protein restriction, supplement with IM hydroxycobalamin and carnitine
biotinidase deficiency - inheritance, pathway involved, sx, tx
biotinidase can’t recycle biotin or free it to be used. AR
p/w sz, hypotonia, ataxia, hearing/vision loss, alopecia, ketoacidosis, high ammonia, organic aciduria
tx with biotin supp - but once hearing/vision/delays occur can’t reverse them.
partial deficiency = 10-30% enzyme activity
cerebellar vermis hypoplasia, 4th vent cystic dilatation, can be assoc with hydrocephalus and genetic anomalies
dandy walker malformation
Betz cells
UMNs of the nervous system
large cells in primary motor cortex (layer 5)
cortical layers from superficial to deep
I - most superficial - molecular
2 - external granular
3 - external pyramidal
4 - internal granular
5 - internal pyramidal
6 - multiform layer (deepest)
glucocerebrosidase (acid B-glucosylceramidase) deficiency
Gaucher disease (AR)
lysosomal accumulation of glucocerebrosides
types of Gaucher disease-(the-1-i-saw-was-type-2)
Type 1 - hepatosplenomegaly - no CNS involvement
Type 2 - onset before age 2, CNS movement d/o, spasticity, eye probs progress to death by age 2-4 years
Type 3 - onset after age 2, slow progression. BMT may help
enzyme replacement helps liver but not brain
cortical tubers in TSC, what are they made of, do they matter, do they grow
contain big bizarre neurons, abnormal glia, mainly astrocytes.
NOT premalignant
don’t grow, but can look different on MRI over time as kid ages (change in myelination)
tuber burden –> sz burden
GM2 gangliosidosis
deficiency of hexoaminidase A –> Tay Sachs (only alpha subunits)
deficiency of hexoaminidase A & B –> Sandhoff’s disease (beta subunits)
both are AR
difference between Tay Sach’s and Sandhoff’s
BOTH - macrocephaly, cherry red spot, regression
Tay Sachs only affects CNS (HEXA - A only) and Ashkenazi Jews (“A” Sachs)
whereas Sandhoff’s affects CNS + hepatosplenomegaly (HEXB - A and B)
think volleyball player getting hit in head and liver on the sand
nonenhancing calcified nodules on a Ritter/Franz patient
subependymal nodules (versus SEGAs which enhance)
what is benign hereditary calcification of basal ganglia?
Fahr’s disease - calcifications within striatum or thalamus, not nodular like SENs seen in TSC.
deficiency of aspartocylase –> accumulation of N-acetylaspartic acid in brain
Canavan disease
megalencephaly
poor fixation/tracking in new baby with regression, irritability
MRI - diffuse symmetric WM hyperintensity involving U fibers
MRS shows N-acetylaspartic acid peak
Canavan disease - what is deficient/accumulated?
deficient: aspartoacylase
build up: N-acetylaspartic acid
sick baby in NICU who began irritable with poor feeding after birth, then tanked and became hypotonia, with myoclonic sz and was intubated. MRI shows partial ACC, cerebellar hypoplasia. CSF showed elevated glycine. dx and inheritance?
nonketotic hyperglycinemia (glycine encephalopathy)
AR
most common mutation in P -protein of glycine decarboxylase gene
role of sodium benzoate in NKH
decreases plasma glycine but not CSF
can’t reverse neurologic dysfunction
role of sodium benzoate in NKH
decreases plasma glycine but not CSF
can’t reverse neurologic dysfunction
galactocerebrosidase = B-galactosylceramidase = galactocerebroside-B-galactosidase …all different names for the same protein that is defective in what?
Krabbe disease –> leads to accumulation of galactosylceramides in macrophages of WM
baby with exaggerated startle to stimuli, very irritable (crabby), hypertonic –> opisthotonic, blind, regression, demyelinating polyneuropathy with areflexia. death by 1-2 years
Krabbe disease
symmetric demyelination of WM sparing U fibers
globoid cells
diagnostic criteria for NF2
- bilateral vestibular schwannomas of CN 8
- one vest schwannoma + close relative with NF2
- close relative with NF2 + any 2: neurofibroma, schwannoma,meningioma, glioma
- one vest schwannoma + 2 other tumors
- multiple meningiomas and one vest schwannoma
looks like Hurler’s syndrome, but with cherry red spot on macula
GM1 gangliosidosis - coarse facial features, spasticity, regression, cherry red macula
defective protein/gene in GM1 gangliosidosis
defective Beta-galactosidase
GLB1 gene
baby with macrocephaly, dev delay, spasticity, seizures, path slide with long eosinophilic fibers
Alexander’s disease - megalencephaly
Rosenthal fibers
GFAP mutation
TSC1 protein and chromosome
hamartin, chromo 9
TSC2 protein and chromo
tuberin, chromo 16
tigroid appearance of white matter on MRI
Pelizaeus-Merzbacher disease
Pelizaeus Merzbacher disease -
inheritance? gene? clinical features? MRI?
X linked recessive
PLP1 gene
hypomyelinating leukodystrophy
nodding head, pendular nystagmus, abnormal eye movements, ataxia, chorea, dystonia, spasticity
tigroid WM - spares U fibers
alpha-L-iduronidase deficiency. disease and what accumulates?
Hurler’s syndrome, MPS Type I
accumulation of dermatan and heparan sulfate
defect in iduronate sulfatase
Hunter’s syndrome, MPS Type II
accumulation of dermatan sulfate and heparan sulfate
no corneal clouding
ivory colored back lesions
difference between Hurler’s and Hunter’s syndromes (3)
Hurler’s has corneal clouding and nodules on back, AR
Hunter’s - normal eyes, no skin stuff on back, X-linked (hunters need to see their target, X)
zebra bodies on electron microscopy
Hurler’s syndrome(Hunters-got-rid-of-zebras)
represents lamellar material in neurons that makes a layered appearance
PBG deaminase defect
porphyria
problem with heme biosynthesis
most are AD
epidermal nevus syndrome - name 2 examples, risk of what?
Proteus syndrome (asymmetric big tissues/bones), Becker nevus
not all have neuro sx - but nevi on head –> neuro sx
risk of cancer
orange tonsils - Tangier disease (tangerine). mutation in what?
adenosine triphosphate cassette transporter protein deficiency –> HDL deficiency –> very low total cholesterol and high triglycerides
Menkes disease - whats the defect and inheritance
disorder of intracellular copper transport –> TOO LITTLE COPPER! (opposite of Wilson’s –> too much)
kinky hair, no eyebrows , subdurals in baby
X linked
abetalipoproteinemia - how does it present and what is low?
low vitamin E, no apolipoprotein B, anemia
p/w ataxia, gait probs due to both cerebellar involvement and loss of proprio due to posterior column involvement. also have retinitis pigmentosa
Miller Dieker syndrome
lissencephaly
chromosome 17p deletion
midline defects (omphalocele)
X linked disorder with acanthocytes on peripheral smear, cognitive changes, chorea, weakness
McLeod neuroacanthocytosis
person with diabetes and sudden jerks/dance like movements of one arm
hyperglycemia induced hemichorea/hemiballismus
bi-allelic mutations of biotinidase gene on molecular genetic testing
confirms biotinidase deficiency (AR)
enzyme necessary for recycling biotin –> biotin deficiency
biotin is an important cofactor for carboxylation
metabolic ketoacidosis and organic aciduria
tx: biotin supplementation (neuro sx may persist)
subcortical band heterotopia genetics, what kind of brain development disorder? presentation in males vs females?
DCX gene (double cortin protein, microtubules)
X linked
lissencephaly - migration disorder
lyonization (random X inactivation) –> classic lissencephaly in boys, subcortical band heterotopia in females
75% of cases of holoprosencephaly attributed to what genetic defect?
trisomy 13
6 month old with macrocephaly, frontal bossing, prominent scalp veins, lower extremity spasticity and motor delay
hydrocephalus - get CT or HUS
excessive physical growth in first 2-3 years of life, hypotonia, increased risk of intellectual disability/autism
Sotos syndrome
testing for opsoclonus myoclonus
MRI chest pelvis and abdomen
urine VMA and HVA
MIBG scan if MRI negative
5 day old baby with vomiting, jaundice, hepatosplenomegaly, cataracts, reducing substances in urine, gram negative sepsis
galactosemia
galactose-1-phosphate-uridyl transferase deficiency
Rett genetics
MECP2 mutation on chromosome X
methyl CPG binding protein
TIA in a child triggered by crying/hyperventilation
think Moya Moya disease - esp if they show you an angio
boy with Marfanoid features, delays, ectopia lentis
homocystinuria (high homocysteine in blood and urine)
all 1st degree relatives should be screened for homocysteine levels. high false negative rate on newborn screen
AR
tx: pyridoxine and low methionine diet
myeloschisis
most severe form of spina bifida
neural tissue is exposed - high risk of meningitis
GNAQ mutation
Sturge Weber syndrome
most babies with port wine stain do NOT have SWS and will develop normally
port wine stain can be lasered off. glaucoma common in SWS
generalized myoclonus, color vision loss, night blindness, cherry red spot, ataxia and seizures in a teen
sialidosis type I
dx: decrease in skin cultured fibroblast a-neuraminidase
vomiting baby that can’t break down amino acids, valine, isoleucine, threonine, methionine, odd chain fatty acids. dx and tx?
methylmalonic acidemia (AR)
deficient in methylmalonic CoA mutase
Vitamin B12 def-can lead to acquired MMA because it’s a needed cofactor
tx: metronidazole, protein restriction, carnitine supplementation
branched-chain keto-acid dehydrogenase deficiency
maple syrup urine disease
cofactors for the PMS pathway
biotin cofactor for P—>M (propionyl to methylmalonyl)
B12 cofactor for M—>S (methylmalonyl to succinyl)
glucocerebroside accumulation
Gaucher disease (AR)
most common genetic disease in Ashkenazi jews
HSM, bone disease, thrombocytopenia, bleeding
lumbosacral plexus formed from what nerve roots
anterior rami of L1-S4
- anterior divisions of L2-L4 –> obturator nerve
- posterior divisions of L2-L4 –> femoral nerve
sacral plexus
- anterior part of sciatic - tibial nerve
- posterior part - peroneal
myophosphorylase deficiency
McArdle’s disease
AR glycogen storage disorder
second wind phenomenon (sx go away 10 minutes after starting exercise)
tram track calcification
sturge weber
GNAQ mutation
what causes the “mousy” “Musty” odor in PKU?
phenylacetic acid in urine
PKU most often due to deficiency of phenylalanine hydroxylase. impairs phenylalanine –> tyrosine
tx: diet with no phenylalanine, added tyrosine and AAs
deficiency of alpha-galactosidase A (AGA).build-up-of?
Fabry’s disease
build up of globotrialcyleceramide
can present with paresthesias, GI symptoms, vision probs, hearing probs, renal failure in addition to autonomic stuff, HTN, strokes
which urea cycle disorder is the only one that’s not autosomal recessive?
ornithine transcarbamylase (X linked)
poor feeding and elevated ammonia level in newborn
think urea cycle disorder
raised oval shaped skin-colored patches on baby trunk and lower back
shagreen patches
TSC
unilateral headaches with conjunctival tearing that happen >5x per day lasting 2-30 minutes
paroxysmal hemicrania
tx indomethacin
pain over V1 area lasting 1-10 seconds
no autonomic symptoms
primary stabbing headache
Galant reflex
primitive baby reflex - stroke the side of the spine while the baby is prone and hip will curve towards the touch
should disappear by 4-6 months
tonic neck reflex
baby reflex - fencing posture
when head is turned, that ipsi side extends arm and contra arm flexes
should go away by 6 months
crossed adduction in baby
normal primitive reflex - patellar reflex –> crossed adduction of opposite leg. should go away by 7 months
Moro reflex
should disappear by 5-6 months
Landau reflex
when the baby “supermans” in horizontal suspension (remember lois LANEdau was Superman’s gf)
appears around 4-6 months, goes away after 1 year
HIV in kids-manifestations
basal ganglia calcifications, hepatosplenomegaly, microcephaly, FTT
HIV encephalopathy - regression, spasticity, movement disorders, myoclonus, epilepsy
Kearns-Sayre syndrome
mtDNA deletion
onset before 20 years, pigmentary retinopathy, progressive external ophthalmoplegia , ataxia, cognitive probs, hearing loss
NF2 tumors
vestibular schwannomas
other schwannomas (CN III)
meningiomas
spinal ependymomas
gliomas
ataxia telangiectasia testing
elevated serum AFP
elevated CEA-carcinoembryonic-antigen
low IgG, IgA, IgE
together these labs are 90% sensitive
brain MRI may show cerebellar atrophy
avoid Xrays (impaired DNA repair)
kids with spina bifida prob have allergy to what
Latex randomly?!!!
68% allergic to latex!
can boys have subcortical band heterotopia?
not as common as in girls, but yes - if they have mosaicism
most cases are DCX gene which is X linked
but some are PAFAH1B1, sporadic mosaic mutation after conception.
can range from severe ID and sz in infancy to normal IQ and focal sz in teens/adults
maple syrup urine disease treatment
protein restriction
episodes of ataxia and dark urine (maple syrup urine)
looks like hurler’s but cherry red spot
GM1 gangliosidosis
beta- galactosidase mutation
autosomal recessive
NCLs - match the number to the type (congenital,
10 - congenital
1 - infantile (first year)
6, 4 - late infantile or adult
8 - late infantile
cytochrome B deficiency
mitochondrial mutation
myopathy, exercise intolerance, renal probs, cardiomyopathy
myophosphorlyase deficiency
McArdle’s - muscle fatigue with exercise
glycogen storage type 5
can’t high 5 because muscle cramps and myoglobinuria
AR
elongator complex protein 1 defect
Riley Day = HSAN 3 = familial dysautonomia
AR
merosin defect
congenital muscular dystrophy
point mutation in PMP22
NOT a deletion or duplication…can be AR or AD
CMT3 (dejerine sottas)
CMT1E
congenital hypomyelination
vomiting baby with reducing substances in urine
galactosemia
remove lactose AND galactose from diet!
PDH deficiency inheritance
depends on what component of PDH complex is messed up
most common is X linked
others are AR
PDH deficiency presentation
variable, neonatal vs infancy with lactic and pyruvic acidosis , episodic exacerbations triggered by infection, stress, carb loads
suspect in kids with high lactate and pyruvate, and low lactate:pyruvate ratio
tx with keto diet and thiamine supplementation
treatment of propionic acidemia
protein restriction
biotin (and carnitine) supplementation
metronidazole may decrease production of propionate by gut bacteria
positive Filipin test
Niemann Pick type C - cant esterify cholesterol (messed up intracellular cholesterol trafficking) so it accumulates in perinuclear lysosomes
dev delay, liver stuff, lipodystrophy (inverted nipples). dx?
congenital disorders of glycosylation (carb-deficient transferrin in CSF and blood)
increased very long chain fatty acids + liver and kidney stuff
Zellweger’s
peroxisomal
glycine encephalopathy
partial ACC + elevated CSF glycine
AR
irritable newborns with poor feeding, progressive encephalopathy with myoclonus, resp failure
EEG burst suppression
defect in proteins that make up mito glycine cleavage system –> glycine accumulates everywhere. most common mutation in P protein (glycine decarboxylase gene)
accumulation of galactocerebrosidases in macrophages
Krabbe disease - mutation in galactocerebrosidase (aka galactocerebroside-B-glactosidase, galactosylceramidase)
B-galactosidase deficiency
GM1 gangliosidosis
buildup of gangliosides in brain/organs
looks like Hurler’s but with cherry red spot
TSC genes, proteins and chromosomes
TSC 1- hamartin protein on chromo 9
TSC 2 - tuberin protein on chromo 16
Sanfilippo’s syndrome
MPS III - accumulation of heparan sulfate only
Down syndrome MRI brain findings
small, underdeveloped frontal lobes + small, thin superior temporal gyri
which is the most common urea cycle disorder
OTC deficiency, X linked
what’s the most mild urea cycle disorder
arginase deficiency, presents in adulthood
tx of urea cycle disorders
restrict nitrogen intake (low protein diet)
give essential amino acids, arginine supplementation (except in arginase def)
sodium benzoate, sodium phenylacetic acid and dialysis during acute episodes
mannitol for brain edema
filamin A mutation
periventricular nodular heterotopia (AKA subependymal nodular heterotopia)
X linked dominant (fatal in boys)
messed up cytoskeleton stabilization
lab findings in homocystinuria and treatment
increased blood and urine levels of homocysteine, homocystine, and methionine
tx: give B6 (some forms respond), low protein diet, betaine (converts more homocysteine to methionine), folate and B12 (may also help conversion to methionine)
homocystinuria with LOW methionine levels
deficiencies of:
Methylene THF reductase
methionine synthase
buildup of globotriasylceramide
Fabry disease
alpha galactosidase A deficiency
