Myotonic Dystrophy: Genetics & Inheritance Insights
G
e
n
e
t
i
c
s
o
f
M
y
o
t
o
n
i
c
D
y
s
t
r
o
p
h
y
1
MDF Myotonic Dystrophy DAY
University of Florida, Gainesville
Deborah Barbouth, MD, FACMGG
June 29th, 2019
G
e
n
e
t
i
c
s
1
0
1
2
C
h
r
o
m
o
s
o
m
e
s
3
Expansion of CTG in the
DMPK
gene
(protein kinase) for DM1
Expansion of CCTG tetranucleotide
CNBP
(
ZNF9
) gene for DM2
W
h
a
t
c
a
u
s
e
s
M
y
o
t
o
n
i
c
D
y
s
t
r
o
p
h
y
?
4
O
n
e
n
u
c
l
e
o
t
i
d
e
i
s
o
n
e
l
e
t
t
e
r
i
n
t
h
e
g
e
n
e
A
,
T
,
C
,
o
r
G
R
e
p
e
a
t
e
x
p
a
n
s
i
o
n
5
One nucleotide is one letter in the gene
A, T, C, or G
T
r
i
n
u
c
l
e
o
t
i
d
e
i
s
3
n
u
c
l
e
o
t
i
d
e
s
C
A
G
,
C
G
G
,
C
T
G
,
C
T
A
,
e
t
c
.
T
r
i
n
u
c
l
e
o
t
i
d
e
r
e
p
e
a
t
e
x
p
a
n
s
i
o
n
6
One nucleotide is one letter in the gene
A, T, C, or G
Trinucleotide is 3 nucleotides
CAG, CGG, CTG, CTA, etc.
T
r
i
n
u
c
l
e
o
t
i
d
e
r
e
p
e
a
t
i
s
a
r
e
g
i
o
n
o
f
t
h
e
s
a
m
e
3
n
u
c
l
e
o
t
i
d
e
s
o
v
e
r
a
n
d
o
v
e
r
a
g
a
i
n
C
T
G
C
T
G
C
T
G
…
T
r
i
n
u
c
l
e
o
t
i
d
e
r
e
p
e
a
t
e
x
p
a
n
s
i
o
n
7
One nucleotide is one letter in the gene
A, T, C, or G
Trinucleotide is 3 nucleotides
CAG, CGG, CTG, CTA, etc.
Trinucleotide repeat is a region of the
same 3 nucleotides over and over again
CTGCTGCTG…
W
e
e
x
p
e
c
t
e
v
e
r
y
o
n
e
t
o
h
a
v
e
d
i
f
f
e
r
e
n
t
n
u
m
b
e
r
s
o
f
r
e
p
e
a
t
s
(
b
u
t
w
i
t
h
i
n
t
h
e
n
o
r
m
a
l
r
a
n
g
e
)
T
r
i
n
u
c
l
e
o
t
i
d
e
r
e
p
e
a
t
e
x
p
a
n
s
i
o
n
8
When the repetition of three nucleotides in a
gene gets too big and causes the gene to no
longer function properly
T
r
i
n
u
c
l
e
o
t
i
d
e
r
e
p
e
a
t
e
x
p
a
n
s
i
o
n
Nussbaum, McInnes and Willard; Thompson and Thompson, Genetics in Medicine ,
A
u
t
o
s
o
m
a
l
D
o
m
i
n
a
n
t
I
n
h
e
r
i
t
a
n
c
e
10
S
o
m
e
i
n
t
e
r
e
s
t
i
n
g
f
a
c
t
s
Anticipation
is the phenomenon that
the symptoms become more severe or
start at an earlier age as a disease is
passed on to the next generation
Father vs Mother
. The likelihood of
repeat expansion differs between
spermatogenesis and oogenesis.
M
y
o
t
o
n
i
c
D
y
s
t
r
o
p
h
y
1
Schaaf, Zschocke and Potocki; Human Genetics: From Molecules to Medicine
Conceive naturally
CVS or Amnio
In vitro fertilization with preimplantation
genetic testing
Costly
Adoption, sperm/egg donation, etc.
F
a
m
i
l
y
p
l
a
n
n
i
n
g
o
p
t
i
o
n
s
13
Go through the IVF procedure
Once embryos are obtained they are
tested for DM
Lab may ask for samples from additional
family members
Those embryos that test negative for DM
are implanted
Cons
Cost
No guarantee
I
V
F
w
i
t
h
P
r
e
i
m
p
l
a
n
t
a
t
i
o
n
G
e
n
e
t
i
c
T
e
s
t
i
n
g
14
https://www.iasoivf.com
T
h
a
n
k
y
o
u
15
Explore the genetic basis of Myotonic Dystrophy, including trinucleotide repeat expansions in the DMPK and CNBP genes, leading to impaired gene function and symptoms. Learn about autosomal dominant inheritance and the phenomenon of anticipation in symptom severity.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
Genetics of Myotonic Dystrophy MDF Myotonic Dystrophy DAY University of Florida, Gainesville Deborah Barbouth, MD, FACMGG June 29th, 2019 1
What causes Myotonic Dystrophy? Expansion of CTG in the DMPK gene (protein kinase) for DM1 Expansion of CCTG tetranucleotide CNBP (ZNF9) gene for DM2 4
Repeat expansion One nucleotide is one letter in the gene A, T, C, or G 5
Trinucleotide repeat expansion One nucleotide is one letter in the gene A, T, C, or G Trinucleotide is 3 nucleotides CAG, CGG, CTG, CTA, etc. 6
Trinucleotide repeat expansion One nucleotide is one letter in the gene A, T, C, or G Trinucleotide is 3 nucleotides CAG, CGG, CTG, CTA, etc. Trinucleotide repeat is a region of the same 3 nucleotides over and over again CTGCTGCTG 7
Trinucleotide repeat expansion One nucleotide is one letter in the gene A, T, C, or G Trinucleotide is 3 nucleotides CAG, CGG, CTG, CTA, etc. Trinucleotide repeat is a region of the same 3 nucleotides over and over again CTGCTGCTG We expect everyone to have different numbers of repeats (but within the normal range) 8
Trinucleotide repeat expansion When the repetition of three nucleotides in a gene gets too big and causes the gene to no longer function properly Nussbaum, McInnes and Willard; Thompson and Thompson, Genetics in Medicine ,
Some interesting facts Anticipation is the phenomenon that the symptoms become more severe or start at an earlier age as a disease is passed on to the next generation Father vs Mother. The likelihood of repeat expansion differs between spermatogenesis and oogenesis.
Myotonic Dystrophy 1 Schaaf, Zschocke and Potocki; Human Genetics: From Molecules to Medicine
Family planning options Conceive naturally CVS or Amnio In vitro fertilization with preimplantation genetic testing Costly Adoption, sperm/egg donation, etc. 13
IVF with Preimplantation Genetic Testing Go through the IVF procedure Once embryos are obtained they are tested for DM Lab may ask for samples from additional family members Those embryos that test negative for DM are implanted Cons Cost No guarantee https://www.iasoivf.com 14
Thank you 15
