FISH

SMALL SUPERNUMERARY MARKER CHROMOSOMES

- sSMC +21 -

           References

 

Down syndrome due to a free trisomy 21 may be (in rare cases) accompanied by presence of an additional sSMC.
Such cases are here collected.

Frequency of sSMC plus trisomy 21 among Down syndrome patients (according to {6}): 3 of 25,817 cases with Down syndrome; the same paper concludes, that there is no increased risk of trisomy (21) in carriers of sSMC.


Cases without sSMC but with Down's syndrome (47,+21) from parents with SMC (47,+mar)
Described in Refs: {9, 18, 19, 20, 21, 22}

 

                     
  case no.  gender/ age at diagnosis studied 
material
de novo/ 
inherited
GTG-banding result
grade of mosaicism
final result of the sSMC test
methods
clinical symptoms reference  
  +21-
U-1
male/
1m
PBL de novo 48,XY,+21,+mar[28]/
47,XY,+21[7]
min(4)(:p12→q11:) 
partial maternal iso-UPD 4p16:
cenM
subcenM; UPD-test
Down syndrome {1} case 10
{2}
 
  +21-
U-2
female/
at birth
PBL maternal 47,XX,-14,+t(14;21)
(p11;p11),+mar[?]
inv dup(15)(q11.2 or q12) radioactive ISH with pML34 Down syndrome {3; 4; 5}   
  +21-
U-2a
male/
1m
PBL de novo 48,XY,+21,+mar[22] inv dup(15)(q10) cenM;
subcenM
Down syndrome {1} case 23  
  +21-
U-3
to 5
?/
?
? ? 48,+21,+mar n.a. n.a. Down syndrome {8} original literature not available  
  +21-
U-6
male/
1m
PBL de novo 48,XY,+21,+mar (bisatellited)[?] n.a.  n.a. Down syndrome {7} case 6  
  +21-
U-7 
female/
1m
PBL de novo 48,XX,+21,+mar (bisatellited)[?] n.a. n.a. Down syndrome {7} case 7  
  +21-
U-8 
female/
1m
PBL de novo 48,XX,+21,+mar (bisatellited)[?] n.a. n.a. Down syndrome {9}   
  +21-
U-9 
male/
1m
PBL de novo 48,XY,+21,+mar (bisatellited)[?] n.a. n.a. Down syndrome {10}   
  +21-
U-10 
female/
1m
PBL de novo 48,XX,+21,+mar (bisatellited)[?] n.a. n.a. Down syndrome {11}   
  +21-
U-11 
female/
1m
PBL de novo 48,XX,+21,+mar (bisatellited)[?] n.a. n.a. Down syndrome {12}   
  +21-
U-12 
female/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {13} case 4  
  +21-
U-13 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {14} original literature presently not available  
  +21-
U-14 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {15} original literature not available  
  +21-
U-15 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {16} original literature not available  
  +21-
U-16 
female/
1m
PBL maternal 48,XX,+21,+mar[?] n.a. n.a. Down syndrome {17}   
  +21-
U-17 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {18} original literature not available  
  +21-
U-18 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome {19} original literature not available  
  +21-
U-19 
?/
1m
PBL ? 48,+21,+mar[?] n.a. n.a. Down syndrome  {20} original literature not available  
  +21-
U-21 
male/
prenatal
AF maternal 48,XY,+21,+mar[?] n.a. n.a. pregnancy terminated {21} case 2  
  +21-
U-22
female/
1m
PBL de novo 48,XX,+21,+mar[45%]/
47,XX,+21[55%]
r(14)
negative for D22Z4 and positive for D14/22Z1
FISH with all available centromeric probes Down syndrome  {23} case 7  
  +21-
U-23
female/
prenatal
AF n.a. 48,XX,+21,+r[60%]/
47,XX,+21[40%]
r(14 or 22)
ring present in 80% of lung tissue
FISH with all available centromeric probes see below {24;25} case 23  
Amniocentesis due to advanced  maternal age; Down's syndrome; thus pregnancy terminated; no Down's syndrome typical signs
  +21-
U-24
female/
1w
PBL maternal
due to a karyotype 46,XX,t(14;21) (q11.1;p11.1)*
47,XX,t(14;21)
(q11.1;p11.1),+21
sSMC is here the der(14)t(14;21)
(q11.1;p11.1)
n.a. n.a. Down syndrome  {26}   
  +21-
U-25
?/
1w
PBL familial n.a. n.a. n.a. Down syndrome  {27}   
  +21-
U-26
male/
postnatal
PBL familial 48,XY,+21,+mar n.a. n.a. Down syndrome  {28}   
  +21-
U-27
male/
postnatal
PBL n.a. 48,XY,+21,+mar n.a. n.a. Down syndrome  {29}   
  +21-
U-28
male/
postnatal
PBL n.a. 47,XY,+21/47,XY,+mar/
?48,XY,+21,+mar/?
46,XY; mar in 50% of the cells
min(7)(:p11.1
q11.21:)[10]/
r(7)(::p11.1

q11.21::)[1x]/
min(7)(:q11.21-p11.1:
:p11.1
q11.21:)[9]
cenM
subcenM
Down syndrome  {0} provided by Dr. B Zoll, Göttingen, Germany  
  +21-
U-29
female/
postnatal
PBL familial 48,XX,+21,+mar[100%] inv dup(13)(q11) or
inv dup (21)(q11.1)
M-FISH; cenM
subcenM
Down syndrome  {0} provided by Carme Fuster,  Barcelona, Spain  
  +21-
U-30
male/
1m
PBL n.a. 48,XY,+21,+mar[90%]/
47,XY,+21[10%]
min(22)(pterq11.22:) cenM, subcenM; CES-specific probes see below {0} provided by Dr. Mazauric, Düsseldorf, Germany  
normal pregnancy, born by sectio cesaraea; Down syndrome with AVSD and Morbus Hirschsprung
  +21-
U-31
female/
1m
PBL de novo 48,XY,+21,+mar[10]/
47,XY,+21[30]
inv dup(22)(q11.1) cenM, subcenM Down syndrome {0} provided by Dr. Huhle ,Leipzig, Germany  
  +21-
U-32
male/
adult
PBL n.a. 48,XY,+21,+mar[1]/
47,XY,+21[29]
r(13)(::p1?2q1?3::)[1]/
der(13)(pter
q?12.11:
:p11.1
q1?3:
:q11.1
p1?1.2:)[2]
cenM, subcenM Down syndrome {32}  
  +21-
U-33
female/
7m
PBL de novo 48,XX,+21,+mar n.a. n.a. Down syndrome  {30}   
  +21-
U-34
female/
2y
PBL de novo 47,XX,der(14)t(14,21),
+mar[100%]
47,XX,t(14;21)
(q11.1;p11.2),+21
cenM, subcenM Down syndrome {33} case P-8  
  +21-
U-35
male/
7y
PBL de novo 48,XY,+21,+mar[100%] der(13 or 21)t(13 or 21;18)(13 or 21pter13q11 or 21q11.1:
:18p11.21
18p11.32)
M-FISH, subcenM Down syndrome {37}   
  +21-
U-36
male/
2m
PBL mat 46,XY,der(14;21)(q10;q10),+mar[100%] min(14)(:p11q11:) centromeric probes Down syndrome {31}  
  +21-
U-37
male/
prenatal
AF n.a. 48,XY,+21,+r(16)(p11.2q11.2)[11]/47,XY,+21[19] mar(16)(:p11.2q11.2:)
array: 31.65-45.07 MB
array-CGH Down syndrome {0} provided by Dr. S.W. Cheung,  Houston, USA  
  +21-
U-38
female/
postnatal
PBL
(EKF-
cellbank)
pat 48,XY,+21,+mar[100%] inv dup(13or21)(q10) cenM, subcenM Down syndrome {0}  
  +21-
U-39
male/
prenatal
fibroblasts n.a. 48,XY,+21,+mar[11]/
47,XY,+21[4]
min(22)(pterq11.21) cenM, subcenM Spontaneous abortion - maybe due to combination of trisomy 21 and sSMC {35} case 26  
  +21-
U-40
male/
newborn
PBL mat
for mother see 14-O-q11/2-1
47,XY,rob(13;21)(q10;q10),+21,+mar*  min(14)(:p11q11:) cep probes Down syndrome {34}  
  +21-
U-41
male/
4m
PBL n.a. 47,XY,t(4;19)(p16.3;p13.2),inv dup(21)(q10),+inv dup(21)(p10) SKY, subcenM Down syndrome {0} provided by Dr. Aniko Ujfalusi, Hungary  
  +21-
U-42
male/
newborn
PBL fam 47,XY,+21,+mar  n.a. aCGH Down syndrome {36} case 1  
  +21-
U-43
n.a./
prenatal
AF n.a. 47,X,+21,+mar[15]/
46,X,+21[2]
min(Y)(pterq11.1) subcenM Down syndrome {0} provided from Poland
 
                     

 

 


References