Yếu tố di truyền gây bệnh tự kỷ ở trẻ em: Hiện trạng và các phương pháp chẩn đoán

Tap chi Cling nghe Sinh hoc
12(1): 1-9, 2014
BAI TONG QUAN
YEU
TO DI TRUYEN GAY BENH Tir KY
.
O THE EM: HIEN TRANG VA CAC PHIXONG
PHAP CHAN DOAN
Le
Bic Vi0, Nang Van Hal, Nguyen Huy Mang
Vien Nghien ctitt he gen, Vien Han lam Khoa hoc vet Cong nghe Viet Nam
Ngay nhan bai:18.8.2013
Ngay nhan clang: 05.3.2014
TOM TAT
Trong thoi doi phat trien, benh to IcS/
r
a
ng
can tar nen pha bien trong xa hc)i,.dac
.
Wet la
a
tre

Khi
benh mai ducc phat hien,
nguai to
cho rang nguyen nhan gay benh chit yeu do yeu to mai truing song,
str

thieu quan tam tir cha me va nh4ng nguai co trach nhiem day do. Tir da se clan den firth twig tre kern phat trien

toin dien ve mat neon nga, giao tiep va gag hoat clang xa
,
hai. Thai gian
gin
day, viec nghien ciru can benh nay
da
cO met buoc
tien mai
khi
cac nha khoa hoc da bat dau tim ra nhitng gen c6 kha nang gay benh do xay ra
hien Wong dot bien gen. Tir day, mat nhan dinh duoc dua ra de là benh tkr kjr co the c6 kha nang di truyen
to

bo
,
me sang con cal. Trong so nhung gen c6 kha nang gay benh, gen
SHANK3
yeu to
dung
vao ir6 quan trong
nhat, ben canh nhCrng gen khac n
h
u
NLGN3, NLGN4X,
FISH (floumescent in situ hybridization) va aCGH
(array comparative genomic hybridization) la hai phuong phap chinh duce sir dung
de
phat hien
nhung sai
khac tren gen hay tren nhiem sac the, ben canh d6 de xic nhan lai nhung thay dal do, phuong phip MLPA

(multiplex ligation probe amplification) se duce clung den. Ben canh viec tim ra nhung rot loan ye di tntyen,
nhimg lieu phap chera tri cling dirge ap dung de gin!) cho benh
nhan cc!,
the mph dan han trong viec giao tiep,
trong nhung hoot dang xa hai va nhan biet nhung sit vat, hien tuong xung quanh. Tuy nhien, cho den nay, mat
cau hei van chtra co lai giii la sit twang quan gifra kieu hinh, kieu gen cita benh va sv twang tic gifra nhimg yeu
to di truyen va hoar' girth m8i tnreng. Trong tuang lai gin, neu nhung thic mac nay c6 lei giii dap chinh xac
thi se
la mat tien ba
len trong viec
ngan chart va dieu tri can benh nay.
Tit khoa: aCGH, benh ttr 4, di truyJn, &Of ban gen, FISH,
gen
SHANK3, MLPA
GIOI THIEU
Dinh nghia ve
bdnh tv
kY' len dAu
tiep duqc nha
khoa hoc nguai My Leo
Kanner dua ra vao nam
1943. Khi d6, ttr ky ducfc cho là benh gay ra nhimg
•
rot loan phat trien he than kinh a nguai benh bang
cach lam thay dOi su lien ket va to chin giaa
to
bao
thAn kinh va cac khop than kinh. Benh thuOng bee
phat ngay tv khi benh nhan con nh6, nett kitting duric
phat

hien semi va co
nhang lieu phap dieu tri thich
hop, benh se ngay cang nang han va
benh
nhan
thuong c6 xu htrang tranh xa moi hoat &Ong xung
quanh mirth, khong muon tiep xtic
vii
nguai Ichfic va
c6 nhung hanh ding bit thu6ng.
Ve
ca
ban, su thieu nhung hoat deng va giao
tiep xa hai, nen nga la diu hien not bat trong
moi

berth nhan tv Icy. Dar Ming là tieu chuin yang de
chin doin lam sang doi vii nhung ngirtri bi nghi nga
mac tv ki tai cac Benh vien chuyen khoa Nhi.
Nguyen nhan ma tin tnrac den nay van duoc cho la
nye tiep va chit yeti nit& la sv thieu quan tam, chain
s6c
dimg each tir cha mg nal rieng va
cac bac nuoi
day n6i chung. Chinh dieu nay da khiAn cho tit
khong ductc
,
phattrien met each toan dien

the

,

chat,
tinh than va dac
biet là he than
kink.
Lau
dan,
nhung
roi loan ve
than kinh tang dan len, tao nen 06
roi loan tu ky (autism
spectrum disorders - ASD)
yeti
niang bieu hien rat ro rang ve tinh each, hanh Ong
va
suy nghT (Autism Association, 1994).
Thai gian gin day, vii
nhung
nen ba nhay 'KA
trong y hoc, sinh hoc phan tir, sinh hoc to bao, chin
doin, mat nguyen nhan mai gay bath tkr kjf da
,
ittroc
tim ra. DO nhOng sv
roi loan
chuyen h6a, mat can
bang sinh hOa trong ca
the do det bien
tren cac gen

chirc nang gay ra. Nhiffig gen nay m4 Ma cho clic
protein lien quan
trVc tiep den he thong than kinh
va
nhting khap than kinh trong ca
the.
Do do, (tat
bien xay ra
ten nh!ng gen nay se
tnjc tiep
gay ra
nhang h6i
chung
roi loan thAn kinh c6 bieuhien
lam sang
giOng nhu benh tv kY. Mang det bien clAu
1
0.012
0.01
0.009
0.008
.00625
ar

0.006
0.004
0.004
0.001
0.002
O. 00 11

0
■
0.01
0.0065
0.005
,

0 .0 0.1
0.008
0.0012 0.0015

sCs
4
-\
6' 0
1
"
1
o,
a
" 4
9
'
ce
\I
P
S
b
Cl=
4

4
V
s
•

e
-V"

""k
s
•
(sP

,N1
tien da duqc tim thy tren cac gen inh hu6ng den
kh6p thin kinh nhu gen
SHANK3
(SH3 and
multiple ankyrin repeat domains 3) (Gauthier
et al.,
2009; Moessner
et al.,
2007)
NLGN3
(Neuroligin 3)
va
NLGN4X
(Neuroginin 4, X-linked) (Jamain
et
al.,

2003; Laumonnier
et al.,
2004). Trong do,
nhung d6t bien tren gen
SHANK3
duqc cho la yeu
to chit yeu hcm tat ca giy ra ph8 rOi loan tq kY hay
con goi la h6i chimg Phelan — McDermid (Durand
et al.,
2007). Ben canh do, sq ph& trien cUa ceng
nghe giai ma town b6 he gen ngu6i ding viec tim ra
nhung bien the s6 lumg ban sao chep (copy
number variations — CNVs) da gifip tim ra duqc
nhung bien the di truyen
.
giy inh
hung
16n den
benh

kY
cling
nhu khang dinh met cich chic
chin tam quan trong cua chirc 'tang khop thin kinh
d6i vai benh tr k9 (Autism Genome Project, 2007).
Cac nghien ceu sau de da tim ra nhung CNV ten
phirc he gen
NLGN-NRXN-SHANK
Ara hai gen !chop
thin kinh Mac nhu

SynGAP va DLGAP
(Berkel
et
al.,
2010; Marshall
et al.,
2008; Pinto
et al.,
2010).
Tuy nhien, cho den nay, tucmg quan giea kieu hinh
vi kieu gen dm benh nhin van chua duqc lim
sang to.
Trong bii bio nay, chUng toi de cap den cac
phucmg phi!) sinh hoc phin tir de Oat hien (let
Wen gen giy benh
de
tit d6 c6 the chin dofin benh
nhanh hon (tong th6i gifip cac bac &I dua ra
nhung
16i khuyen heti ich cling nhu phip
s
dieu tri
dung din.
1XNH

VA CAC YEU TO DI TRUYEN
ANH HONG
Le Bic Viet
et al.
TInh hinh b?nh tv ky hi4n nay

Tien the gi6i, nhung nghien ciru yr trtrac nam 1985
ve
tS l I:41th tv lc* va nhung dieu kien lien quan
cho ket qui 5 tru&ng hqp troll 1000 tre em dual
18 tuoi. Te nhung nam 1980, so ca mac benh duqc
chin doin thanh c8ng tang len vOi t6c d6 nhanh
ch6ng. Met Olin la do nhung tien 136 cua y hoc
chin doin va chinh phli cling da diu to nhieu ham
vac) Unit vqc y
to
dOC
biet là nhung benh lien quan
den thin kinh (Blumberg, 2013). Trung tam Kiem
sat vi Phong ch6ng benh (CDC) 6 My da dua ra
t9 le tre mac nhung rOi loan tkr ky tren town ciu
hien nay dat mem 12 ca trong 1000 tre em
(American Autism Centers, 2011). Tai My,
ts,
le
tlr
k9 tinh tlr nhung nam 1980 den nay di tang gip
den 10 lin, uorc tinh 1/110 tre em (1%)
duqc
chin
doin mic
,
benh. Dieu nay
a
ding duqc giii thich
bai loi

s
ong ngAy cang thqc dung tai My. Ben
canh
my,
Anh cling IA met mac co t9 le tq kjr dat
muc cao (xip xi 1%) (Autism Society, 2006).
Ngoai Anh vi My co ty le mac tlr k9 cao, benh
nay cling co inh huerng tren khap cac qu6c gia
tren the gi6i. Tuy nhien, rat kh6 de xac dinh chinh
xic tY le nay. Posserud ding c6ng skr (Autism
Society, 2010; Autism Speaks, 2008) da th6ng
ke
ts, le tv ks
,
cua
met s6 qu6c gia tren The gi6i trii
deu tren khap cac Chau lqc (tre Chau Phi) dqa
tren sq chin elan tkr kY 6 cac tre em song tren dit
nuac de (Autism Speaks, 2008; Posserud
et al.,
2010) (Hlnh 1). Do ty 1(9 co the xiy ra dOng th&i
va a
bi nham Ian vai nhieu benh khic ye mat thin
kinh nen de tinh toan chinh xic tY le mac benh
la

met viec tucrng doi kh6 khan.
Hinh
1. Tlnh hInh bOnh tit
kjr

tai
mOt
s6
quOc gia
hen thO giai.
Tap chi Cling nghe Sinh hoc
12(1): 1-9, 2014
Tai Viet Nam, cho den nay van chua c6 met dieu
tra, thong ke chinh thirc ve benh
to
kSr. Neu chieu
theo ti le cua Anh quec, Viet Nam hien c6 83 trien
dan thi c6 160.000 ngu&i to VS/. Ben canh do, theo so
lieu
cita Be Thucmg binh vi Xa hei c6 khoang tir 5-
7% tre em tan tit 6 dO tuoi clued 15, trong de tre em
to 1(9 va bai nao chiem khoang tren 40%. Ngoai ra,
trong so nhung tre ducc chin doin xic djnh li to IcS,
trong giai doan ttl. 2008 — 2011, chi Ichoing 12% so
tre duqc phit hien cic diu hieu cua berth truck 2
tuoi; 19,74%
so
tre duqc phit hien li do co giao chit
khong phai b8 mg hay 8ng bi; 56,58% tre duqc phit
hien benh nha diu hieu chim not (tre da han 2 thing
tuoi). Ben canh do, theo nghien cuu me hinh tan tit
&
tre em cua Khoa Phuc hoi chirc nang Benh vien Nhi
Trung uang, giai doan 2000-2007, so lucmg tre duqc
chin doin va dieu trj to lc

Se
ngay cing
s
deng; tre to k9
den khim nam 2007 tang gap 50 lan so vii nam
2000;
s6
tre to IcS
,
den dieu tri nam 2007 tang gip 33
lan so yeti nam 2000. Xu the mac to lcSr tang nhanh tir
122% den 268% trong giai doan 2004-2007 so yin
nam 2000. Theo cic thong ke tir Berth vien Nhi deng
I, TP HO Chi Minh, nam 2000, Benh vien chi dieu trj
cho 2
,
tre
bj
to k9, thi sau 4 nam con se nay da li 170
tre, den nam 2008 con so nay tang gip gin 2 lan tirc
la 324 tre.
Bieu hien lam sang binh ter 1[5
,

6
benh to 1c9, rei loan phit trien he thin kinh
chinh la Neu hien lam sing tieu bieu nhit. N6 bao
gem nhieu
trieu chimg khic nhau & ngu&i benh, tip
trung lai ph6

rOi loan to icy (autism
spectrum disorders
- ASD). Trong do, n6i
,

nhat chinh li so kern phit
trien toan din tre mac benh, dac biet IA kha nang sir
dung ngen nprei kern, chim biet n6i; ngai hoac khong
muen giao tiep van ngtr&i khic; tir do din den cic hoat
deng xa hei bj kim ham met cich tei da.
DOi vii nhung hinh dOng sinh hoat hang ngiy, tre
thuting co xu htreing
lam nhung
viec lap di lap lai theo
bin nang ma khong chju
ngei yen met
ch6 hay con
goi la hien tuong tang deng (Lam and Aman, 2007).
Hien Wong nay lai bao gem nhieu bieu hien khic nhu
ngu&i benh hay c6 hinh dOng quay co tay, quay diu
hay c6 nhung hinh Ong c6 tinh bat buec vi du nhu
xep de
chaff, bitp be,
,
0 to thinh met hang ngang hoac
doc. Nguy hiem nhat chinh la benh nhan l
ai
hay to
lam
minh bj thuong

nhu: lay tay choc len mat, dm len
da, to danh vao tay, vao dau. Met nghien cuv vao nam
2007 da bao cao ve hien wow nay vii ti le 30% benh
nhan c6 dau hieu
rei
loan to kk (Dominick
et aL,
2007).
M6t van
da
nava la
Ire mac benh thuong c6 khi
'tang di lai chim han nhieu so vii tre Ichic, thuong
phii mit 2-3 num tuoi mai di lai binh thuong duqc.
Ngoai ra, kha tang lien lac bang mat cita tre thoc so
kheng
tot
vi benh nhi thuong c6 thii de he( hung vii
moi thir xung quanh.
Nhiing
yiu to gay
benh b
cap
de di
truyen
hue
Benh to 1c9
,
c6 nen tang di truyen
rat

manh, n6
Bong
Op len den khoang 90% kha 'tang benh to Ic9
phit trien & tre em va thong thu&ng duqc chi ra bei
cic gen ttrcmg ung (Hallmayer
et al.,
2011). Mac di'
viy, so di truyen benh rat phirc tap vi khong re rang
(Abrahams and Geschwind, 2008; Buxbaum, 2009).
Nhiing nghien ciru ye nhung cap song sinh da cho
thay so di
truyen
benh to 1c9 c6 xic suit la 0,7 vi dei
vii
phe roi loan to kS
,
len an 0,9. Dac biet doi yen
nhang cap song sinh la con gii thi kith nang di
truyen to IcS
,
gap tai 25 lin so vii ngu&i binh thuong
(Geschwind, 2009). Tuy nhien, cho den nay, nhifmg
det bien c6 nguy ca gay to ky vi 016
r6i loan tkr
ky

van chua duqc xic djnh het. Nhung diet Wen nay c6
the là det bien don gen (det bien chi xiy ra tren met
gen) hoac IA nhang bien dei bat thu&ng tren nhiem
sic the (NST). Nhung det bien NST nay gay ra

ntrOng hei chirng benh khic nhau lien quan den phis)
rei loan to kjf (Abrahams and Geschwind, 2008).
Nguyen nhan gay benh bit
nguen tir
nhi
-
mg hien the
so Itrong sao chep (copy number variations) tren gen
qui djnh, nhung bien
the
nay c6 the li mat doan, lap
doan, them doan, dio doan tren gen hoac NST (Cook
and Scherer, 2008). Berth to Ic9 c6 tinh di truyen
nhung Ichong chic chin c6 tinh ke filth. Dieu de the
hien & ch6: con cai mac benh tuy nhien be mg van c6
the hoan toan binh thu&ng, khoe manh duqc goi
la

ngu&i mang mam benh (Beaudet, 2007).
Thai gian
gin
day, met
s6 gen
vi NST c6
nguy ca gay ra to Ic9 vi phe rOi loan to k
,
S, da
duqc cic nhi khoa hoc tim ra.
Nhung
det bien vi

bien doi bat thu&ng tren nhiing gen nay gay ra
nhting hei chimg khicnhau, tang vii mOi loai
phe red loan to Ic9 vi mei hei chirng duqc dat ten
theo nha khoa hoc da phit hien ra n6: hei chirng
Asperger vii gen
NLGN3 va NLGN4X
(Jamain
et
al.,
2003; Laumonnier., 2004); hei cluing Phelan-
McDermid vii gen
SHANK3
(Durand
et al.,
2007; Gauthier
et al.,
2009; Moessner
et al.,
2007), hei chirng nay con co ten khac la hei
chirng
x6a NST 22q13. CA 3 gen nay deu c6 diem
chung la anh htrang troc
tiep den
so phit trien
cua
trung tam than kinh.
3
Le Bic Viet
et al.
Gen

SHANK3
ma h6a cho met loai protein lien
quan truc tiep den cac khap than kinh giau proline.
Gen nay nam tren NST canh dai 22q13. Ve mat chat
nang, gen
SHANK3
la mot thanh vien trop lien hQ
gen
SHANK.
Cac protein
SHANK
deu bao gom nhieu
vOng (domain), la nhiing protein xoan hinh
,
khan,
duqc sinh ra ki sau phin bao. Chung

ket tivc
tiep diem thy cam he thong can
truyen
than kinh, cac
kenh ion va nhang protein mang khac den actin
cytoskeleton va G-protein. Protein SHANK kheng
nhthig ce chirc nang kiem soat to chac mit dO khap
than kil!' ma con c6 }chi nang tao phirc he receptor
khap thin kinh, phin tir tin hieu va protein lien quan
den to bao xuang c6 trong tity cOt song (Boeckers
et
al.,
2002; Naisbitt

et aL,
1999). Trong do, protein
SHANK3 c6 the tao lien ket yeti to bao protein thin
kinh (Meyer
et al.,
2004). Do viy, trong so 3 gen
chirc nang anh huang den henh tu kSr
ke
tren, gen
SHANK3
duqc coi la nhin to ce anh huang manh
me

nhit de giy ra pho rAi loan tv kS
,
a ngu&i benh. Gen
SHANK3 la
met gen c6 kich thuac rat
Ion
len den
khoang 60 kb, bao gOm 23 exon. Trong de exon 23
co kich thuac dai nhat va eking vai Ire quan trong
trong viec *ay ra hOi chang x6a
NST
22q13 - met
hOi chimg rat dac
trung cua
H)
p roi loan to kjt.
Gen

NLGN3 nam
tren NST X ma h6a cho
protein Neuroligin-3, la met thanh vien trong lien hQ
protein neuroligin trong nhOrn cac protein be mat
to bio thin kinh. Neuroligin tham gia vao ciu tao va
dinh hinh nen trung tam he thong thin kinh. Nhiing
bien the (mit, them, dao doan) tren gen nay di duqc
xac dinh, tuy nhien toan bO trinh tu doan gen cho den
nay yin chua duqc xac dinh chinh xac.
Gen
NLGN4X
ma h6a cho protein Neuroligin-4,
X-link. Protein nay din* thuOc hQ neuroligin nen
cimg ca vai fro *An giOng nhu neuroligin-3. Gen
NLGN4X
ding nam tren NST X, c6 kich thuac
Ichoang
5,5
Mb. Khac vai gen
NLGN3,
hi4n
nay, mai
chi c6 2 bien the duqc xac dinh tren gen
NLGN4X.
WO Men teen gen
SHANK3 va
hOi chfing x6a NST
22q13
Nhiing hien the tren gen
SHANK3 hau

hit la
mat met doan DNA Ian, do dO hien Urging nay con
g9i la hpi chang xoa NST 22ti13. HOi
,
chirng nay
mang gin nhu dAy

m9i diu hieu rOi loan dm
benh to kS, nhu da neu a tren, do da gen nay duqc
coi nhu nhin to chu ch8t trong viec giy benh
tg

Icy. Trong do, dOt bien x6a toan be exon cuoi hinh
thanh hei chung benh rat dien hinh cua hqi chirng
Phelan-McDermid, ten g9i khac la hOi chung x6a
NST 22q13. Hien tuqn* mit doan tren NST 22q13
bit nguon tir nhaing mat doan nucleotide, skr hoan
vi gen hoac su thay doi cau
trfic anh
huang den
NST canh dai 22. Kich thuac doan gen bi x6a tren
NST 22q13 thuang dao dOng trong Ichoing 100 kb
den 9 Mb chia lam 3 loai da la: xoa met doan nho,
xoa doan rat nh6 va xoa doan Ian. Nhimg nghien
ciru
truac day da chi ra x6a doan nh6 giy ra pho
roi loan dac trung cua benh tu kSt, x6a doan lon co
xu
,
huang giy ra nhang kieu hinh nghiem

trQng
nhit va x6a doan rat nh6 mang nhising diem ca ban
cua
hOi chang x6a NST 22q13 da dirge bao tir
tnrac (Moessner
et al.,
2007). Bonaglia cung tong
skr da liet ke duqc nhang mit doan tren NST
22q13 tren 42 benh nhan nghien ciru (Bonaglia
et
al.,
2011) (Bang 1).
Bang 1. Danh sach nhCrng
mat
doan m6iduvc
tim thay tren NST 22q13.
Banh
Gi6i
Plurcrng phap
Nhiem sac tha
Loai dat Won
Kich thveoc
Ngulin gOc
nhan
tinh
doan bi xoa
di
truyen
1
Nam

FISH
Del(22)(q13.3)
X6a nucleotide tai exon
cuoi
0.9 Mb
Cha me
2
NO
,

Phan tich NST
Del(22)(q13.31)
X6a nucleotide tai exon
cu6i
5.38 Mb
Cha me
3
ND
FISH
Del(22)(q13.32)
X6a nucleotide tai exon
cuOi
2.5 Mb
Me
4
Nam
FISH
Del(22)(q 13.32)
X6a nucleotide tai exon
cuOi

1.64 Mb
Chua xac dinh
5
NCr
Phan tich NST
Del(22)(q13.31)
X6a nucleotide tai exon
cuOi
6.5 Mb
Cha me
6
Nam
FISH
Del(22)(q 13.32)
X6a nucleotide tai exon
cu6i
2.65Mb
Me
7
Nam
FISH
Del(22)(q13.31)
X6a nucleotide tai exon
cuOi
3.5 Mb
Me
8
Nam
Phan tich NST
Del(22)(q13.32)

X6a nucleotide tai exon
cu6i
8.1 Mb
Cha me
9
NCr
FISH
Del(22)(q13.31)
X6a nucleotide tai exon
cuOi
0.8 Mb
Cha me
10
NCr
Phan tich NST
Del(22)(q13.2)
X6a nucleotide tai exon
cuoi
8.1 Mb
China xac dinh
11
NCr
aCGH
Del(22)(q13.31)
X6a nucleotide tai exon
cuOi
4.98Mb
Cha me
4
Tap chi

Gong ngh" Sinh hoc
12( 1
):
1-9, 2014
12
NO
,

aCGH
Del(22)(q13.3)
X6a nucleotide tai exon
cuoi
1.08 Mb
China xac dinh
13
NO
,

Phan tich NST
Del(22)(q13.31)
X6a nucleotide tai exon
cuoi
5.8 Mb
China xac dinh
14
Nam
Phan tich NST
Del(22)(q13.2)
X6a nucleotide tai exon
cuoi

7.6 Mb
Cha me
B§nh
Gibs
Pturceng phap
Nhiem
sac the
Loai
d6t bran
Kich thuhfrc
Ngu6n g6c
nhan
tinh
doan bj x6a
di truyen
15
NO'
FISH
Del(22)(q13.31)
X6a nucleotide tai exon
cuoi
4.7 Mb
Chu
,
a xac dinh
16
Nam
FISH
Del(22)(q13)
X6a nucleotide tai exon

cuoi
3.7 Mb
Chive xac dinh
17
NO'
Phan tich NST
Del(22)q(13.2q1
X6a nucleotide tai exon
cuoi
7.2 Mb
Cha me
3.3)
18
NCr
FISH
Del(22)(q13.31)
X6a nucleotide tai exon
cu6i
4.7 Mb
Mg
19
NO
,

FISH
Del(22)(q13.32)
X6a nucleotide tai
exon cuoi
1.9 Mb
Mg

20
Nam
aCGH
Del(22)(q13.31)
X6a nucleotide tai exon
cu6i
3.4 Mb
Cha me
22
NO
,

aCGH
Del(22)(q13.32)
X6a nucleotide tai exon
cu6i
1.8 Mb
Cha me
23
NCr
aCGH
Del(22)(q13.31)
X6a nucleotide tai exon
cuoi
3.4 Mb
Cha mg
24
Nam
aCGH, MLPA
Del(22)(q13.33)

X6a nucleotide tai exon
cuoi
-122 Kb
Cha me
25
NO'
aCGH
Del(22)(q13.33)
X6a nucleotide tai exon
cuoi
-122 Kb
Cha me
26
Nam
FISH
Del(22)(q13.31)
X6a nucleotide tai exon
cuoi
4.4 Mb
Cha me
27
Nam
FISH
Del(22)(q13.31)
X6a nucleotide tai
exon cuoi
-4 Mb
Cha me
28
NCr

Phan tich NST
Del(22)(q13.2)
X6a nucleotide tai exon
cuoi
9.0 Mb
Cha me
29
Nam
aCGH
Del(22)(q13)
X6a nucleotide tai exon
cuoi
122 Kb
Cha me
30
NCr
Phan tich NST
Del(22)(q13.2q1
X6a nucleotide tai exon
cuoi
7.4 Mb
Me
3.3)
31
NO'
Phan tich NST
Del(22)(q13.31q
X6a nucleotide tai exon
cuoi
5.8 Mb

Cha mg
13.3)
32
NO'
aCGH
Del(22)(q 13.3q 1
X6a nucleotide &
giO
,
a
NST
-74 Kb
Cha me
3.3)
33
NO
,

aCGH
Del(22)(q13.3q1
3.3)
X6a nucleotide b giCya NST
-44 Kb
Cha mg
34
Nam
aCGH
Del(22)(q13.3q1
X6a nucleotide & giDa NST
-18 Kb

Chiya xac dinh
3.3)
35
NCr
aCGH
Del(22)(q13.3q1
X6a nucleotide 6
,
giCra NST
-27 Kb
Chu
,
a xac dinh
3.3)
36
Nam
aCGH
Del(22)(q13.3q1
X6a nucleotide a gift NST
-39 Kb
Chiya xac dinh
3.3)
37
NCr
Phan tich NST
Del(22)(q13.32)
Ring 22
2.16 Mb
Cha me
38

NO'
Phan tich NST
Del(22)(q13.33)
Ring 22
1.2 Mb
Chu
,
a xac dinh
39
Nam
Phan tich NST
Del(22)(q13.31)
Ring 22
5.2 Mb
Me
40
NCr
Ph5n tich NST
Del(22)(q13.33)
Ring 22
0.45 Mb
Me
41
Nam
Phan tich NST
Del(22)(q13.31)
Ring 22
3.2 Mb
Cha me
42

Nam
Phan tich NST
Del(22)(q13.32)
Ring 22
2.04 Mb
Cha me
CAC PHUONG PHAP CHAN DOAN 0 CAP DO
PHAN TU, TE BAO
Nhu di nal u tren, nhang d6t bi6n hay nhang bien
the so luting sao chep tren nhirng gen chirc nang lien
quan den he thong thin kinh anh huang den benh to kY
hau het la nhang mat doan, lip doan hoic dao doan. Do
d6, de Oat hien &roc nhirrig bat thuang nay, doi hoi
phai
can
Ai) dung ca flitting phuong phap sinh hoc phan
to ciing nhu sinh hoc to bao. Nhang phtrang phap hien
dai va dang duac clang ph6 bien nhat hien nay la array
comparative genomic hybridization (aCGH),
fluorescence in situ hybridization (FISH). Ben canh do,
multiplex ligation probe amplification (MLPA) la in6t
phuang Olaf) ding rat hiTru ich &roc dung
,
nham xac
nhan lai nhang mat doan hoc d6t bien diem di tim
5
Le
Bic Viet
et al.
they bang cac phucmg phap traac do. Ngoai 3 phucmg

phap hay clang den a tren, phuong phap giai trinh iv the
he mai di buac dau duqc img dung nha lcha nang doc
duqc trinh to met doan DNA caa ne.
Phtrang phip array comparative genomic
hybridization (aCGH)
aCGH la met phuong phap duqc sir dung de xac
djnh nhen bien the trong phien ban sao chep caa
genome nhu them hoac mat NST hay met phan NST.
Ve
nguyen li tien hash phuong phap aCGH, man dua
vao thi nghiem lute phai gem it !that 2 Mau, do la man
'dem tra (test) va mau doi chimg (control). Nheng
mau

nay la DNA tong so di duqc tach chiet tir trtrac do va
hoin toan dO dieu Ici'e'n ve de tinh sach. Mat khac,
phuong phap doi hoi nhang matt do dac hieu cho
nheng (loan DNA nghi ng6 bj x6a hoac chen them
nucleotide. Mau de nay la nheng doan oligonucleotide
co kich thuac tir 20-85 nucleotide. Cuei cling, yeu
to

Ichong kern phan quan tong khac caa aCGH la nheng
tin hieu lai (hybridization signals). Tin hien lai nay la
nheng mau huSmh quang duqc nhuem vao man lam
tra, trong !chi mau doi chimg duqc nhuem vai met loai
mau dac trung khac. Trong phucmg phap aCGH, tin
hieu lai nay chinh la yeo to quan tong
de
nhan biet c6

hay Ichong nheng su bat thuang trong gen/doan DNA
ma minh dang nghien cau.
Dua vao phucmg phi') nay, 10 dot bien va 14 (let
bien mit doan tren NST 22q13 Ian lugt di phat hien
thay tren cac nghien ciru cita Bonaglia va Soorya cling
cac cong su (Bonaglia
et al.,
2011; Soorya
et al.,
2013).
Phtroug phi') gild trinh ttr the he mai
Giai trinh to the he mai (illumina dye sequencing)
la met ki thuat ducc sir dung
a
xac djnh 4 loai cac
baza nits tren doan DNA dua ten nhimg mau quknh
dac hieu cho mOi loai bazo nits. Su tien be cua
phuong phap nay the hien 6 the n6 c6 the xac djnh
duqc trinh to a ca nheng 'yang khe doe va nheng trinh
to lap lai. Trong nghien ciru oh Chaste ding cling
cong stir, phuong phap giai trinh ttr mai tren may
illumina di buac dau duqc img dung de phat hien 5
bien the tren met se gen va NST c6 lcha nang gay phe
rei loan to kk (Chaster and Leboyer, 2012).
Phuong phdp MLPA
icy thu4t
MLPA (multiplex ligation probe
amplification) la met ki thuat sir dung nheng man del
(probe) dac hien duqc khuich dai nh6 phan img PCR
nham sang loc nhimg (let bien thuong gap tren

nheng gen chirc nang gay benh di truyen. Be Kit
MLPA duqc thucrng mai h6a tir cong ty MRC
Holland, Amsterdam, Ha Lan. Vai tro
.
chinh caa
MLPA trong nghien

benh
ttr
Ick la nham kiem tra
xac nh4n lai ket (let bien mit 'Joan hoac dot bien
diem di duqc tim thay nha phuong phip cac phucrng
phap phan tich NST hoac giai trinh AL Cho den nay,
di co tong cong 37 mall de duqc sir dung cho NST
22q13 va 4 trong so de dac hien cho gen
SHANK3.
Plurong phap FISH
FISH (lai huknh quang trong to bao) la met ki
thuat di truyen hoc to bao duqc cac nha nghien ciru y
sinh hoc phat then vao dau nheng nam 1980.
Phuang phap nay clung de phat hien va khoanh vimg
cac diem mat hoac ellen them nucleotide 6 cac trinh
tv DNA trong NST. FISH sir dung nheng mau do
huknh quang gan vao nhimg phan mong muen
cua

NST. DO phat hien nhang yang gin dm mau do
huknh quang len NST, kinh hien vi huknh quang can
duqc sir dung. FISH thuang duqc sir dung de tim ra
nhang diem dac tnmg trong DNA nham dua ra

nheng 16i khuyen di truyen, xac djnh loai va thuoc
mai. Doi vai phuong phap nay, met mau do can
duqc thiet ke. Mau de phai c6 kich thuac du km de
lai met cach dac hieu vai DNA dich nhung cling
khong duqc qua Ian se rat de gay kim yam qua trinh
lai. Mau de duqc gan duOi truc fiep vai huknh
quang, can vai DNA dich la Idling the.
Thuc te, FISH la phuong phap di truyen hoc to
bao ducc biet den nhieu nhat trong viec phat hien
nhemg bat thuang tren NST (Durand
et al.,
2007).
TOng cong di c6 28 OA bien mit doan di tim thay
trong nhang nghien ciru cua Bonaglia va Soorya
ding cong su ve benh to Ick (Bonaglia
et al.,
2011;
Soorya
et
al., 2013).
TIXONG QUAN GICJA KIEU ILINH VA KIEU GEN
Met trong nheng yin de quan tong nhtmg chua
duqc giai quyet ki cang la viec am hieu nheng mei
ttrcmg quan gift bien the di truyen va kieu hinh benh
to kk. Gia thuyet dau tien li giai tinh Ichong den
nhat ye kieu hinh cua benh trong suet qua trinh phat
trien gay ra su cham phat trien co the 6 ngeri benh.
MOt gia thuyet khac la nguyen nhan gay benh den tir
ca
nheng bien the hiem va thuang gap. Mac du cac

nghien can co lien quan trtrac day van chua dua ra
duqc nheng bang chirng re rang ye nguyen nhan c6
nguOn gec tir nhtmg hien the ha?
,
gap 6 benh tu
.
kk,
nhung
cac phan tich gan day ye nheng bien the di
truyen lien quan den phe roi loan to Ick di dua ra gqi
k rang ca nheng bien
the
hiem hay thuang gap deu
6
Tgp chi Cong nghe Sinh hQc
12(1): 1-9, 2014
c6 the gay ra phO rOi loan tv ky do sir lign loan cfra
mang ltrai than kinh (Ben-David and Shifman,
2012). Gia thuyet cuOi cling, khong lien quan den hai
gia thuyet tru6c do, la nguyen nhan bat nguan
tir

nhung yeu to mai truing lam thay doi kieu hinh.
SU' TUONG TAC GIUA YEU TO DI TRUYEN
VA MOI TRUONG (GxE)
Nheng sir khong ang nhAt ve met di truyen c6
the duqc ly giai la do flirting nghien ciru lien quan
den benh tv ky van con kha it. Tuy nhien, nheng ket
qua nay con c6 the duqc lam sang to drra tren khung
hinh mau twang tic GxE (D'Amelio

et al.,
2005).
Ben canh nhung nguyen nhan ye di truyen dA &Km
neu a tren, nheng tranh cal xung quanh nguyen nhan
bat nguon tra moi truing not len nhu benh nhan c6
tiep xtic vai
nhung
loai kim loai nAng c6

thu8c
tna sau, thuoc diet co, benh truyen nhiem do virus
hay nhung hoa chat dOC hai thai ra moi tnnang.
MAc du Meng ket qua ban du thu (URN la rat
dang khich le, nhtrng gia dinh va benh nhan c6
lien

quan den benh tv ky van clura duqc ma rOng nghien
dm den sir Wang tic GxE. M'et trong nhung van
de
chinh trong hinang nghien ciru nay do la kha nang de
phat hien nhung twang tic GxE thuang it kha thi
hon

kha nang phat hien nhung anh huong rieng re dr di
truyen hay moi truing. Nheng nghien ciru ye twang
tic GxE a trong nhung 1:18i cheng kilt loan thin kinh
khac nhau dang din bi lang xwingdo thieu di nhung
ket qua tich cuc (Duncan and Keller, 2011). Tuy
nhien, nhung ket qua nghien ciru nay van can thiet
bai

chfing glut) chung to hieu hon ve tinh khong lien
trong nhirng nghien ciru ttr twac

den nay va
tir

Q6 Qua an
nhung
gqi him ich ve phuang phip
ngin chAn benh tir sarn.
CuAi ding, nhung nghien ciru tiep theo ve moi
twang quan giea nhung bien the hiem gAp c6 lien
quan den pho rOi loan tit ky va nhung yeu to moi
twang tren nhung benh nhan mang cfic dOt bien da
duqc xic dinh c6
the
se rat hen ich. Tuy nhien,
de

thuc hien duqc dieu do cling khong
he
a
ding do ,s6
ltrqng ngtnai mang mam benh kh6ng nhieu.
'CET LUAN
Cho den nay, nhO sir phat trien cita khoa hQc
cOng nghe, dAc biet la linh vuc di truyen hQc da dua
den nheng quan niem mai ye ca the phan flit va to
bao gay ra benh tu Icy. NO khong chi din gian la do
nhung yeu to moi truing ben ngoai tic amg, ma con

c6 the do ca nhung rOi loan chric nAng gen. Nhieu
cau hal mai se not len, bao gem vai tra cita nhung
bien
the
hay gAp va sir tuong quan gift kieu hinh va
kieu gen oh benh. Cuoi ding nhung cling khong
kern phan quan trong, str am hieu ye su tuang tic
gift nh(tng yen to di truyen va hoan canh moi tnnang
la
rat can thiet doi vai nghien tiro benh li cita hr ky,
tuy nhien de di sau vao nghien ciru su Wang tic nay
can doi hoi mot Wong mau benh lin va thai gian
nghien ctru lau dii.
Uri cam an:
Cong trinh nghien citu
.
nay duqc Myr
hien bang sy.
ho
try
kink
phi dm de tai cap ca
sd

Vien Nghien ctiu
he
gen, Vien Han lam Khoa hQc
va

Cling nghe Viet Nam.

TAI LIEU THAM KHAO
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Mutations in the SHANK2 synaptic scaffolding gene in
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Genet
42: 489-491.
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reported Autism Spectrum Disorder in School-aged U.S.
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syndrome.
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of autism spectrum disorders.
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11:
35-43.
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environment, and gene-environment interactions.
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associated with neuropsychiatric conditions.
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919-923.
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Muscarella LA, Guarnieri V, Militemi R, Bravaccio C,
Elia M (2005) Paraoxonase gene variants are associated
with autism in North America, but not in Italy: possible
regional specificity in gene-environment interactions.
Mol
Psychiatry
10: 1006-1016.
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Folstein S (2007) Atypical behaviors in children with
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Duncan LE, Keller MC (2011) A critical review of the first
10 years of candidate gene-by-environment interaction
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Chaste P, Fauchereau F, Nygren G, Rastam M, Gillberg
IC, Anckarsater H (2007) Mutations in the gene encoding
the synaptic scaffolding protein SHANK3 are associated
with autism spectrum disorders.
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Laurent S, St-Onge J, Lapointe L, Hamdan FF, Cossette P,
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C (2003). Mutations of the X-linked genes encoding
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David A, Moizard MP, Raynaud M, Ronce N, Lemonnier
E, Calvas P (2004) X-linked mental retardation and autism
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(2004) The complexity of PDZ domain-mediated
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Szatmari P, Scherer SW (2007) Contribution of SHANK3
mutations to autism spectrum disorder.
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Regan R, Conroy J, Magalhaes TR, Correia C, Abrahams
BS (2010) Functional impact of global rare copy number
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Posserud M, Lundervold AJ, Lie SA, Gillberg C (2010)
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(2013) Prospective investigation of autism and genotype-
phenotype correlations in 22q13 deletion syndrome and
SHANK3 deficiency.
Mol Autism
4: 18
8
Tap chi Cong nglie Sinh h9c
12(1): 1-9, 2014
GENETIC FACTORS CAUSING AUTISM IN CHILDREN: STATUS AND DIAGNOSIS
METHODS
Le Bac Viet, Nong Van Hai, Nguyen Huy Hoang*
Institute of Genome Research, Vietnam Academy of Science and Technology
SUMMARY
In the modem life, autism is becoming more and more popular in society, especially children. Originally,
it was believed that the major cause of this disease is due to environmental factors such as lacking care of
parents or teaching responsible people. Therefore, children patients are delayed in entire development of
languages, communication and social activities. In recent years, studies of autism have been obtained a great
breakthrough when scientists found out genes getting involved in this disease due to mutagenesis. Thus, a
consideration was brought out that autism may be well a heritable disease from parents. Among related genes,
the
SHANK3
gene is the main contribution factor, beside the
NLGN3
gene,
NLGN4X
gene Array
comparative genomic hybridization (aCGH) and floumescence in situ hybridization (FISH) are two main
methods applied for autism-related genes/chromosomes analysis. Moreover, multiplex ligation probe
amplification (MLPA) technique is used to confirm results obtained by two methods above. After diagnosising
genetic disorders, some treatment therapies should be implemented in order to encourage autism patients be

positive in communicating, social activities and recognizing everything around. However, up to now, two
issues which are still debatable and unsolvable, are the relationships between phenotype-genoype and the
interactions between genetic factors and environmental backgrounds. In the near future, if these wonders are
answered, there will be a significant step in prevention and treatment of autism.
Keywords: aCGH, autism, FISH, genetic, MLPA, SHANK3 gene
* Author for correspondence: E-mail:
nhhoangaigrac.vn
9