Single Gene Disorders Flashcard

most common cause of Familial Hypertrophic Cardiomyopathy (what does this protein do?)
B-Myosin heavy chain mutation (part of myosin motor unit)
2nd, 3rd most common cause of FHCM?
2nd cardiac troponin (anchor troponin to tropomyosin)
3rd cardiac myosin-binding protein (anchor myosin to titin)
mutated gene in achondroplasia? function of gene? mutated gene affect?
FGFR3 98% G to A (growth absent) – negatively regulates bone growth. Mutation constitutively activate it.
inheritance of achondroplasia
new mutation %. when die inutero
auto dominant. 80%. homozygous
Thanatophoric Dysplasia. Lethal? phenotype?
yes, lethal, born with extremely short limbs.
Osteogenesis Imperfecta mode of inheritance?
Auto Dominant
Osteogenesis Imperfecta Type 1
blue sclera. mutations in aa’s other than glycine. normal stature, lil deformity.
Osteogenesis Imperfecta type 2. what substitution?
lethal, Type II OI – Gly substitution
Osteogenesis Imperfecta – what part of gene mutation = most severe?
1. Glycine (allow collagen to pack close together)
2. C Terminus (start of collagen wrapping)
3. mutation in alpha1 gene (twice level of expression than beta)
EDS (Ehlers Danlos), type 1 phenotype?
cigarette scars, large joint hypermobility, skin hyperextensibility.
EDS (Ehlers Danlos) – most lethal? why? phenotype?
type IV – rupture of arteries, colon, gravid uterus.
no hyperflexiblity, translucent skin.
EDS (Ehlers Danlos) type I & IV inheritance mode?
auto dominant
EDS (Ehlers Danlos) type VI. inheritance. what gene? phenotype?
auto recessive. lysyl hydroxylase gene. hyperextensibile skin, joint hypermobile, blind, bleending in eye.
EDS (Ehlers Danlos) type VII. inheritance? what gene? function of that gene?
auto recessive. cleavage site for N-protease mutated thus can’t convert pro-collagen to collagen.
Marfan Syndrome, 3 distinctions?
Arachnodactyle, ectopic lentis, aortic aneurysm.
Marfan Syndrome inheritance? what 2 cardiovascular problems?
auto dominant. aortic aneurism & mitral prolapse.
Marfan Syndrome, what mutation?
FBN1 gene. cystine substitution. Fibrillin also involved.
Marfan Syndrome, phenotype
tall stature, long extremities, pectus excavatum.
Hypophosphatemia – cause
abnormally low levels of phosphate in blood – get softening of bones
Hypophosphatemia – cause
abnormally low levels of phosphate in blood – get softening of bones
Hypophosphatemia, 3 proteins involved? interaction?
NPT2 – sodium-phosphorus cotransporter.
PHEX – protease that inactivates inhibitor of NPT2 synthesis.
FGF23 – inhibits synth of NPT2
X-linked Hypophosphatemia
mutated PHEX – doesn’t inactivate PTN thus NPT2 synth downregulated.
Auto Dominant Hypophosphatemia
gain of function in FGF23 – inhibit synth of renal enzyme producing vitamin D & inhibit synth of NPT2.
heridetary Hypophosphatemia rickets
loss of function of NPT2
Hemochromatosis, inheritance?
auto recessive
Hemochromatosis, lab result?
high transferrin saturation, high serum ferritin levels
Hemochromatosis Rx
phlebotomy (drain blood)
Hemochromatosis, what two proteins controlled by HFE. what does HFE do?
DMT 1 iron transporter & ferroportin (iron exporter). HFE senses how much iron is in blood.
Hemochromatosis – what gene mostly mutated?
C282Y (cystine replaced w tyrosine) incorrect folding – protein degraded – no HFE.
spherocytosis mutation? Rx? elliptocytosis mutation?
ankyrin, splenectomy, spectrin
spherocytosis hereditary pattern, clinical symptoms, which cell type affected
auto dominant, anemia jaundice splenomegaly, RBC affected (shape)
Elliptocytosis – which gene is defective? consequence?
Beta heterodimer (can’t form tetramers)
Epidermolysis Bullosa Simplex. Which protein affected? hereditary pattern? prevelance? phenotype?
Keratin mutation, auto dominant, most common, mild blisters & weber-cockayne subtype & palmoplantar blistering
Epidermolysis Bullosa Junctional: mutation? phenotype?
laminin-5 mutation, elbows & knees blister.
Dominant Epidermolysis Bullosa: mutation? phenotype?
Type VII collagen mutated. arms & legs affected mostly.
Recessive Epidermolysis Bullosa: mutation? phenotype?
Collagen type VII, repeated blistering & scarring of hands & feet, fingers & toes fuse, Squamous cell carcinomas, malignant melanoma, oral cavity blisters.
Polycystic Kidney Disease, what genes mutated? which one more prevalent?
PKD1 & 2 encoding polycystin 1 & 2. Type 1 is more prevalent.
Tuberous Sclerosis: what two genes/proteins prevent this disease? How? What oncogenic category are these genes in.
TSC1 & 2 – they activate Hamartin/Tuberin Complex which inhibit rapid cell growth. They are “Tumor Suppressor Genes”

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