Genetics-mutations

Question 1

genetic mutation in Bloom Syndrome

Answer 1

Mutation in BLM Chromosome 15, band q21.1

Question 2

genetic mutation in Rothmund-Thompson Syndrome

Answer 2

RecQ helicase

Question 3

genetic mutation in Li-Fraumeni Syndrome

Answer 3

P53 tumor suppressor gene

Question 4

genetic mutation in Fibrous Displasia

Answer 4

Gs-alpha receptor-coupled signaling protein

Question 5

genetic mutation in multiple hereditary exostoses

Answer 5

EXT1, EXT2 genes

Question 6

genetic mutation in Ewing Sarcoma

Answer 6

t(11;22) EWS gene of chromosome 22 fuses FLI gene on chromosome 11

Question 7

genetic mutation in Synovial sarcoma

Answer 7

T(X;18): SYT-SSX fusion gene

Question 8

genetic mutation in Myxoid liposarcoma

Answer 8

T(12;16)(q13:p11): FUS-DDIT3 chimeric gene

Question 9

genetic mutation in Duchenne muscular dystrophy

Answer 9

Dystrophin

Question 10

genetic mutation in Osteopetrosis

Answer 10

Carbonic anhydrase type II; proton pump

Question 11

genetic mutation in Fibrodysplasia ossificans progressiva

Answer 11

mutation of the noggin, BMP-1 receptor

Question 12

genetic mutation in Achondroplasia

Answer 12

FGFR-3 :Autosomal Dominant

Question 13

genetic mutation inThanatrophoric dysplasia

Answer 13

FGFR-3

Question 14

genetic mutation in Pseudoachondroplasia

Answer 14

COMP - (Type II cologen) Autosomal Dominant

Question 15

genetic mutation in Hypochondroplasia

Answer 15

FGFR-3

Question 16

genetic mutation in Multiple epiphyseal dysplasia Type I & II

Answer 16

MED Type I =COMP (Type II collagen)
MED Type II = type IX collagen
Both Autosomal Dominant

Question 17

genetic mutation in Spondyloepiphyseal dysplasia

Answer 17

Type II collagen

Question 18

genetic mutation in Diatrophic dysplasia

Answer 18

Sulfate transporter

Question 19

genetic mutation in Schmid metaphyseal chondrodysplasia

Answer 19

Type X collagen - Autosomal Dominant

Question 20

genetic mutation in Jansen metaphyseal chondrodysplasia

Answer 20

PTH/PTHrP receptor Autosomal Dominant

Functional defect in parathyroid hormone

Question 21

genetic mutation in Cleidocranial dysplasia

Answer 21

Runx2 (cbfa-1) - Autosomal Dominant

impaired intramembranous ossification

Question 22

genetic mutation in X-linked hypophosphatemic rickets

Answer 22

A cellular endopeptidase

Question 23

genetic mutation in Hypophosphatasia

Answer 23

Alkaline phosphatase gene

Question 24

genetic mutation in familial osteolysis

Answer 24

OPGL;RANKL

Question 25

genetic mutation in Mucopolysaccharidosis type I (MPS I)

Answer 25

alpha-L-iduronidase

Question 26

genetic mutation in Mucopolysaccharidosis type II (MPS II)

Answer 26

Iduronate sulfatase; X- linked

Question 27

genetic mutation in Mucopolysaccharidosis type III (MPS III)

Answer 27

Heparan N-sulfatase or N-acetylglucosamine 6-sulfatase

Question 28

genetic mutation in Mucopolysaccharidosis type IV (MPS IV)

Answer 28

Mucopolysaccharidosis type IV (MPS IV)

Question 29

genetic mutation in Osteogenesis Imperfecta

Answer 29

Type 1 collagen (variable inheritance Type 1 & 4 dominant)

Question 30

genetic mutation in Ehlers-Danlos syndrome

Answer 30

Fibrillar collagen gene

Question 31

genetic mutation in Marfan syndrome

Answer 31

Fibrillin - Autosomal Dominant

Question 32

genetic mutation in Apert Syndrome

Answer 32

FGFR-2 Autosomal Dominant

Question 33

genetic mutation in CMT (80-90%time)

Answer 33

PMP22: Autosomal Dominant (80-90%)
connexin gene x-linked recessive (10-20%)
both result in Nerve demyelination

Question 34

Which Osteogenesis Imperfecta types and Autosomal Dominent & Recessive

Answer 34

Dominant = Type I & IV
Recessive = Type II & III
remember type II is fatal after birth

Question 35

What is Rate of malignant transformation of osteohondromas in MHE?
Where typically does this occur?

Answer 35

5%-10% malignant transformation to chondrosarcoma (= Secondary chondrosarcoma)
in older patients
most common in pelvis &mostly low grade Chondrosarcomas
proximal lesions more likely to undergo malignant transformation than distal lesions

Question 36

What is Rate of malignant transformation of solitary osteochondromas

Answer 36

less than 1%