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)(pter→q11.22:) 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?2→q1?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 21pter→13q11 or 21q11.1:
:18p11.21→18p11.32)		 M-FISH, subcenM Down syndrome {0} provided by Dr. Snezana Brankovic Niksic, Belgrad  
  +21-
U-36		 male/
2m		 PBL mat 46,XY,der(14;21)(q10;q10),+mar[100%] min(14)(:p11→q11:) 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)(:p11.2→q11.2:)
 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)(pter→q11.21) cenM, subcenM Spontaneous abortion - maybe due to combination of trisomy 21 and sSMC {0} provided by Dr. Meiner, Halle, Germany  
  +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)(:p11→q11:) 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  
                     

 

 

References