Questions Flashcards
what syndrome do you get when you have an antibody to the centromere of chromosomes? what is the mnemonic?
- CREST SYNDROME
- Calcinosis, raynaud’s, esophageal dysmotility, scerlodactylyl, telangiectasias
what does rifampin inhibit?
- bacterial RNA polymerase
McCune Albright: what is the triad? it is a ___ mutation in the ___ protein leading to increased production of ___
- polyostotic fibrous dysplasia, cafe au lait (coast of maine-sharp borders), endocrine (precocious puberty, hyperthyroidism, Cushings)
- activating
- GNAS
- cAMP
Neurofibromatosis: ___ ___ gene from ___ protein, how do the cafe au lait spots differ from MAS, what is the defect in? how is it inherited? what happens in the eyes? spine? what happens with the tibia?
- tumor suppressor
- neurofibromin which usually inhibits RAS protein
- smooth
- neurofibromin
- autosomal dominant
- lisch nodules/hamartomas
- dystrophic scoliosis
- AL bowing with pseudoarthrosis
what is the carter effect with inheritance? what is a common pediatric foot condition that shows this?
- individuals of the less commonly affected sex carry higher genetic load and are therefore more likely to transmit to their offspring
- clubbed foot (males much more likely to get than females as they have a lower threshold but if the females have it then they are more likely to pass to their offspring)
Down syndrome: what is the chromosome? what is the main problem with ortho and why? what is the most common spine problem? thus they should avoid ___ sports and posterior fusion should occur with ADI > ___ mm, they also commonly have ___ problems that need preop clearance
- trisomy 21
- laxity from overproduction of collagen XI
- atlanto-axial instability
- contact
- 10
- cardiac
Multiple myeloma: most common ___, what is the cause of lytic lesions? what is released that causes inhibition of osteoblasts? ___ on bone scan, what chromosome is involved with this?
- primary bone malignancy
- PTHrP that induce RANK osteoclast activity
- DKK-1
- cold
- 13
Prader willi syndrome: what chromosome? what is the imprinting that happens with this? decreased ___, they are short, and ___ is common
- 15
- paternal genes get silenced thus activating silent maternal genes
- tone
- obesity
Ewings: what is the translocation? what is the CD marker?
- 11;22
- CD99
Translocation review: 11;22? 9;22? x;18? 12;16? 12;22? 2;13?
- ewings
- myxoid chondrosarcoma
- synovial sarcoma
- myxoid liposarcoma
- clear cell sarcoma
- alveolar rhabdomyosarcoma
rickets with low alkaline phosphatase is ___
- hypophosphotasia; usually it is high with rickets
FOP: what is this? ___ of function mutation in ___, how is it inherited? they form bone in response to ___ injuries; ____ hallux valgus
- fibrodysplasia ossificans progressiva (FOP); aka stone man syndrome
- gain
- BMP receptor so BMP 4 is always on
- autosomal dominant
- trivial
- monophalangeal
Fibroblastic growth factors (FGF) work via the ___ ____ ____ to help with ___ growth of the limb
- apical ectodermal ridge
- proximal to distal
Achondroplasia: ____ mutation, what is the inheritance? what zone of the growth plate? ___ shortening meaning the limbs shorten more proximally compared to distally
- FGFR3
- autosomal dominant
- zone of proliferation
- rhizomelic
what is the area that gives rise to the anterior posterior/radial to ulnar development of limbs? what protein is involved with this? excess SHH would cause ___ polydactylyl while underexpression would lead to ___ aka fibular ___
- zone of polarizing activity
- SHH protein
- postaxial
- postaxial hypoplasia
- hemimelia
Fibular hemimelia: ___ tibial bowing, ___-in-___ ankle, absent ___, genu ___; loss of ___ rays of the foot
- AM
- ball-in-socket
- ACL
- valgum
- lateral
Indian hedge hog: master regulator of ____ development; important for regulating BMP prior to the development of ___; upstream from the ___ pathway which then signals ___
- bone
- osteoblasts
- Wnt-beta catenin
- osteoblasts
along with bone homeostasis, wnt pathway is also involved with ___ development pathway
- dorsal/ventral
Nail patella syndrome: aka ___; what do they present with (2 things)? what is the mutation? what pathway does this involve? what is seen in the pelvis?
- hereditary osteo-onychodysplasia
- hypoplastic dorsal thumb and hypoplastic patella
- LMX1B
- Wnt
- iliac horns
Wnt promotes ossification through binding to ___ receptor and causing the gene expression of ___, ___, and ___
- LRP 5/6
- RunX2, osteocalcin, osterix
what are the 2 types of ossification? what is the first fetal bone to ossify? what is the last bone to fuse? what causes the cartilage precursor with one and not the other?
- intramembranous: stem cells form bone directly; primary bone healing, fetal skull, distraction osteogenesis, scapula/flat bones
- endochondral: bone forms from cartilage precursor; secondary bone healing, growth plates, external fixators
- clavicle at 6 weeks
- clavicle at 25-27 years old
- the relative amount of wnt signaling at the beginning which is high with intramembranous but low in the other which has more expression of Sox9 which causes the development of the cartilage precursor
Cleidocranial dysplasia: what is the mutation in? this is a TF that is found only in what type of cells? what do these patients present with?
- Core binding factor 1 (CBF1)
- osteoblasts
- absent clavicles/scapula and skulls issues (unfused sutures)
Mesenchymal stem cells (MSCs): what comes from the MSCs and what causes this?
Hematopoetic stem cells (HSCs): what comes from this?
- osteoblasts: RunX2, CBF1
- adipocytes: PPAR
- myocytes: MyoD
- chondrocytes: Sox9
- monocytes that become macrophages, when many monocytes fuse they become osteoclasts
Osteocytes: what connects them together and how do they communicate? they produce ____, what mechanical environment would this occur? this then blocks the ___ pathway
- canaliculi
- gap junctions
- sclerostin
- low stress such as NWB, space, paralyzed
- Wnt/beta-catenin
Sclerostin: what are some things that decrease its expression from osteocytes? what are 2 genetic disorders? what is the antibody medication that binds to it and decreases it for treatment of osteoporosis?
- mechanical load, pulsed PTH, AS
- sclerosteosis and Van Buchem disease
- Romosozumab
what is another protein that is made by osteocytes along with sclerostin that decreases bone mass? how does this occur?
- DKK-1
- binds to LRP 5/6 and prevents Wnt from binding
RANK is found on the surface of what cell? what binds to this and what makes it? what also binds to RANKL and what makes this? what binds to the monocytes and makes them become a multinucleated osteoclast?
- osteoclasts
- RANKL from osteoblasts and osteocytes
- OPG from osteoblasts
- CSF-1 binds MSF-1
RANKL binds to RANK and activates ___ while ___ binds to osteoclasts to inactivates osteoclasts
- osteoclasts
- calcitonin (tones down Ca)
Bisphosphonates: they inhibit ___, what are the 2 types and what are the mechanisms of each? what is the drug that is an Ab to RANKL?
- osteoclasts
1. nitrogen containing: inhibit farnesyl pyrophosphate synthase (PARZ)
2. non-nitrogen containing: produce an ATP analogue that causes apoptosis of the osteoclasts - denosumab
name 4 notable enzymes and their function with osteoclasts
- Carbonic anhydrase
- Vacuolar H+ channel: Helps pump the Cl ion channel
- Cathepsin K: lysosomal enzyme that helps break down the organic matrix of bone
- TRAP: enzyme expressed that marks bone turnover
In general, AD syndromes are caused by ___ issues while AR syndromes are caused by ____ issues
- structural
- enzymatic/biochemical
Pyknodysostosis: how is it inherited? what is the enzyme? ___ stature and ___ bones
- autosomal recessive
- cathepsin K deficiency
- short
- brittle
Osteopetrosis: how is the most common form inherited and what is the defect? ___ brittle bones with increased rates of ___ due to the immune function osteoclasts play, what is another defect that is much more rare but results in this and is AR for inheritance?
- AD
- Cl channel
- dense
- osteomyelitis
- carbonic anhydrase II
Achondroplasia: how is it inherited? what is the defect? ____ shortening of limbs
- AD
- FGFR3
- rhizomelic
Pseudoachondroplasia: what is the defect? what is the inheritance? what is significant about their rough ER? has ___ involvement
- COMP
- AD
- looks like a fingerprint
- spine
Multiple epiphyseal dysplasia (MED): what are 3 causes? does it have spine involvement? ___ and ___ involvement helps differentiate from perthes; how is it inherited? also has a ___ ER but no spine helps differentiate it from ___, what is a classic finding of the patella that is super rare?
- COMP, Col9 defect, MATN
- no; SED does
- bilateral and symmetric
- AD
- fingerprint
- pseudoachondroplasia
- double layered patella
Spondylo-epiphyseal dysplasia (SED): what is the defect? how is it inherited? has ___ involvement, what are the 2 main spine issues?
- congenita COL2
- AD
- spine
- C1/2 instability from odontoid hypoplasia and scoliosis
Kniest dysplasia: what is the defect? what is the inheritance? ___-shaped femurs
- COL2A1
- AD
- dumbell shaped
Mucopolysaccharidoses: list the 4 types, in general you get accumulation of ___, ___ ___ deficiency
- Hurler’s: worst prognosis
- Hunter’s- x-linked recessive
- Sanfilippo’s
- Morquio’s-most common; normal IQ
- GAGs
- lysosomal enzyme
Hurler’s syndrome: ___ inheritance, ___ accumulates, ___ prognosis, what is the enzyme?
- AR
- heparan/dermatan sulfate
- poor
- alpha-L-iduronidase
Hunter’s syndrome: ___ inheritance, what accumulates? what is the enzyme? what is a common hand pathology?
- X-linked recessive (remember men hunt)
- heparan/dermatan sulfate
- alpha-L-iduronidase
- CTS
Sanfilippo syndrome: inheritance? accumulate? what is the enzyme?
- AR
- heparan sulfate
- heparan sulfamidase
Morquio syndrome: inheritance? enzyme? what accumulates? ___ IQ, have C1/C2 instability from ___ ___
- AR
- galactose sulfatase
- keratan sulfate
- normal
- odontoid hypoplasia
Gaucher disease: ___ storage disease, inheritance? what zone does it affect? ___ ___ femurs, what is the enzyme?
- lysosomal
- AR
- reserve zone
- erlenmeyer flask
- beta-glucocerebrosidase
Osteogenesis imperfecta: what is the defect? inheritance? ___ sclera, multiple fractures and what upper extremity injury is pathognomonic?
- COL1
- AD
- blue
- olecranon apophyseal avulsion
Ehlers-Danlos: what is the defect in? what is the inheritance? joint ___ and dislocation, what vascular problem can kill them?
- COL1
- AD
- hypermobility
- aortic aneurysm
Marfan’s syndrome: defect? inheritance? what kind of lens problem? what aortic issue? arm span > ___, what hand finding?
- fibrillin 1
- AD
- superior ectopic lens
- aortic dissection
- height
- arachnodactylyl
What is a marfanoid patient with a high risk of DVT/PE likely have? what is different about their ectopic lens? what is the tx? what is the enzyme? what is the inheritance?
- homocystinuria
- inferior
- vitamin B6 and low methione high cystein diet
- cystathionine synthase
- AR
myxomas + fibrous dysplasia = ____
Mazabraud’s syndrome
for osteopetrosis, the infantile form (less common) is inherited ___ ___ while the more common adult form is inherited ___ ___
- autosomal recessive
- autosomal dominant
Larsen syndrome: abnormal ___ features with ___, how is it inherited? what must be cleared prior to operative attention is given to hips or joint dislocations?
- facial
- multiple major joints dislocations
- AD or AR
- C-spine clearance
when might you order a skeletal survey?
- multiple myeloma, NAT, MED (like when you have a kid with bilateral physeal involvement you order this which can be diagnostic)
what is predictive of a below knee type of amputation being functional in a patient with tibia hemimelia?
- quad function and lack of knee flexion contracture
