tl_files/tiny_templates/Bilder TL/Header-sSMC.jpg

- sSMC -

CHROMOSOME 21

References

 

             
  Cases without
clinical findings
15 Cases with
clinical findings
19 symptoms  
  similar imbalances - no clinical findings similar imbalances with clinical findings  
  Cases with
unclear clinical correlation
Cases with
neocentromeres
0 tumor
0
 
  similar imbalances  
      DISCLAIMER      

In general 70% of sSMC carriers are clinically normal. The figures here
are based on the bias, that mainly clinically aberrant cases are reported in literature!

           
  UPD (uniparental disomy) cases: UPD 21
mat
UPD21
pat
UPD 21
unclear
 
           

 


the probably non-dosage sensitive pericentric region of chromosome 21


SCHEMATIC CYTOGENETIC DEPICTION

tl_files/tiny_templates/Bilder TL/sSMC/sSMC-21.jpg



SCHEMATIC MOLECULARGENETIC DEPICTION

acc. to UCSC Genome Browser on Human Mar. 2006 assembly [UCSC hg18, 2006]
and available BAC-data/ array-data from cases marked *** mentioned below [MB]

 

[p-tel --- centromere 13.20] uncritical region 16.90 --- 18.10 critical region

Below adapted for UCSC hg19, 2009

[p-tel --- centromere 14.30] uncritical region 17.95 --- 19.15 critical region

 


Clinical symptoms of centromere-near proximal imbalances

 

chromosomal region

21q - proximal (excluding Down syndrome critical region)
symptoms
autism 29 %
developmental delay 86 %
dysmorphic face 86 %
genital abnormalities 14 %
growth retardation 29 %
hypotonia 14 %
mental retardation 29 %
microcephaly 14 %
obesity 29 %
scoliosis 14 %
number of cases (marked with “°” below) 7
 

References

Cases without clinical findings (O)

 

 
  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-O-
q10/
1-1
female/
n.a.
PBL maternal 47,XX,+mar[100%] inv dup(21)(q10) centromeric probes for 13/21 and 14/22 normal female {7} cases III2 and III3  
  21-O-
q11.1/
1-1
n.a./
n.a.
PBL n.a. 46,tROB(21;22),mar[100%] der(21)t(21;22)(q11.1;p11.2)* centromeric probes for 13/21 and 14/22 normal {1} case 2  
  21-O-
q11/
2-1
female/
40y
PBL n.a. 47,XX,+mar[100%] inv dup(21)(q11.1)
aCGH
and FISH: positive for 21p11.2-p11.1
array-CGH; FISH normal female with primary ovarian insufficiency {35} patient 4
{40} case 21-1
 
  21-O-
q11.2/
1-1
3 male
1 female/
adults
PBL maternal see below min(21)(pterq11.2:) wcp 21 see below {22}  
normal; detected during chromosome analysis in the mother who suffered from a tongue cancer; sSMC with high probability not in connection with cancer!
sister 1: 48,XY,+marx2[4]/47,XY,+mar[34]/46,XY[6]
brother 1: 47,XY,+mar[28]/46,XY[22]
brother 2: 48,XY,+marx2[4]/47,XY,+mar[34]/46,XY[6]
son of brother 2:
47,XY,+mar[3]/46,XY[96]
  21-O-
q11.2/
1-2
male/
prenatal
AF de novo 47,XY,+mar[50%]/
46,XY[50%]
min(21)(pterq11.2:) cenM; subcenM; LSI 21; UPD-test amniocentesis due to advanced maternal age; child normal at 1 year of age {0} provided by Dr. Belitz, Berlin, Germany  
  21-O-
q11.2/
1-3
female/
1y
PBL
(EKF-
cellbank)

de novo  47,XX,+mar[5]/
46,XX[20]
min(21)(pterq11.2:) cenM; subcenM; mild ID GGB04574F, 798
provided by Teleton foundation, Italy
 
  21-O-
q11.2/
2-1
male/
prenatal
AF
(EKF-
cellbank)
de novo 47,XY,+mar[31] inv dup(21)(q11.2)
FISH-d
ata: RP11-89H21 (14.85MB) on sSMC
cenM; subcenM; UPD-test see below {0} provided by Dr. Gillessen-Kaesbach, Lübeck, Germany  
  amniocentesis due to advanced maternal age; sectio due to preeclampsia in week 38+3; at 1.5 y normal development - no dysmorphic signs.  
  21-O-
q11.2/
3-1
female/
prenatal
AF n.a. 47,XX,+mar[100%] inv dup(21)(pterq11.2::p10pter) cenM; subcenM; LSI 21 normal child born {0} provided by Dr. Hickmann, Düsseldorf, Germany  
  21-O-
q11.2/
4-1
n.a./
prenatal
PBL pat 47,XN,+mar[30%]/
46,XN[70%]
r(21)(::p1?2q11.2::) cenM; subcenM; LSI2 father normal; normal child born
{0} provided by Dr. Alves, Portugal  
  21-O-
q11.2/
5-1
female/
29y
PBL n.a.  47,XX,+mar[70%]/
46,XX[30%]%]
der(21)(:q11.2~12p1?2:
:p1?2
q11.2:)
cenM; subcenM; habitual abortions {0} provided from Turkey
 
  ***
21-O-
q11.21/
1-1
***
male/
35y
PBL n.a. 47,XY,+mar[100%] r(21)(::p11.1q11.2::)[3]/r(21;21)(::p11.1q11.2:
:p11.1
q11.2::)[2]/
min(21)(:p11.1
q11.2:)[3]
FISH-d
ata: RP11-89H21 (14.85MB) on sSMC
aCGH: 13.78-16.90
cenM; subcenM;
aCGH
repeated abortions in partner, normal male {40} case 21-2
 
  21-O-
q21.1/
1-1
male/
prenatal
AF de novo 47,XY,+mar[?]/
46,XY[?]
min(21)(:p?11.2q21.1:)
FISH-data: RP11-89H21 (14.85MB) on sSMC
wcp probes; subcenM; UPD-test see below {13} case 21-4  
advanced maternal age; ultrasound normal; child born in week 38; weight 3000g; length 51cm; phenotypically normal; normal at 3w and 1 y
  21-O-
q21.1/
1-2
female/
adult
PBL n.a. 47,XX,+mar[100%] r(21)(::p11.2q21.1::)
FISH-data: RP11-89H21 (14.85MB) on sSMC
aCGH: 13,342,486-15,777,892 MB
cenM; subcenM; LSI21 normal female, sSMC also present in unborn child {0} provided by Dr.Zivi Borochowitz; Israel  
  21-O-
q21.1/
2-1
male/
adult
PBL n.a. 47,XY,+mar[100%] r(21)(::p11.2q21.1::)
FISH-data: RP11-89H21 (14.85MB) on sSMC
cenM; subcenM; LSI21
aCGH (Israel)
normal male, repeated abortions in female partner {10}
{13} case 21-3
{21} case 99
{24} case 32
{40} case 21-3
 
                     

 

O-Cases with similar imbalances NOT caused by sSMC (O-IMB)

none reported yet

 

O-cases with unclear/insufficient characterization of the sSMC (CO):

 

 
  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-
CO-1
male/
prenatal
AF de novo 47,XY,+mar[26]/
46,XY[7]
r(21)(::p1?1q1?1::)* centromeric probes; wcp 13, 21 advanced maternal age, normal ultrasound, normal child at 2y {12} case 25  
  21-
CO-2
male/
prenatal
AF n.a. 47,XY,+mar[60%]/
46,XY[40%]
mar(21)(?pterq11.2)
aCGH: 13.55-14.33 MB
aCGH advanced maternal age, normal at birth
{38} case 31  
  21-
CO-2
male/
prenatal
AF n.a. 47,XY,+mar[100%] mar(21)(?pterq11.1)
aCGH: 10.01-10.12 MB
aCGH advanced maternal age, normal at birth {38} case 32  
                     

 


References

Cases with clinical findings (W)

 

 
  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-W-
q11.2~
21.1/
1-1 °
male/
62y
PBL n.a. 47,XY,+mar[5]/
46,XY[15]
min(21)(pterq11.2~21.1:) cenM, subcenM, wcp13, wcp21 see below {0} provided by Dr. J. Vermeesch, Leuven, Belgium  
psychomotor retardation; severe developmental delay; no sexual development; short stature, microcephaly; brachycephaly; large nose, behavioral problems; birth was "difficult" - weight 2850g;
  21-W-
q11.2~
21.1/
1-2 °
male/
newborn
PBL
(EKF-
cellbank)
de novo 47,XY,+mar[5]/
46,XY[10]
min(21)(pterq11.2~21.1:)
FISH-data: break between 15.00 and 24.51 MB
cenM, subcenM, LSI 21; LSI UBE3A; PCL-FISH;
UPD-test (also for #15)
see below {37} case 22
 
Scoliosis of the spine, flat feet with ankles turning in, 22kg at age 4 ( both parents are very slim), was born underweight, wants to eat nonstop; depressed bridge of the nose, autism, delayed fine motor skills
  21-W-
q11.2/
2-1 °
n.a./
postnatal
PBL de novo 47,+mar[50%]/
46[50%]
mar(21)(p?q11.2)*
size ~0.4 MB
n.a. subcenM with 3 BACs see below {19} case 24  
Difficulty with fine motor skills; mild dysmorphic features; small penis.
  21-W-
q11.2 -
q21.3 -
q22.11/
1-1
female/
newborn
PBL de novo 47,XX,+mar[100%] r(21)(::p11.1q11.2:
:q21.3
q22.11::)
array-data: (~12)-15.70MB and 29.28 - 31.12 MB
cep 13/21 BACs see below {33}  
Birth weight 2,370g, Apgar score 7 at 1 min; mild facial dysmorphisms and hypotonia. At 2 months seizures; weight 5,250 g (90th to 97th centile), length 55 cm (25th to 50th centile), general muscular hypotonia, malformed ears, umbilical hernia, gastroesophageal reflux, but neuropsychiatric evaluation, EEG, and MRI of the brain normal; at 5 months weight 11,700 g (>97th centile); later slight delay in psychomotor development, especially speech delay; sitting without support at 7 months, walk without support at 20 months.
  21-W-
q21/
1-1 °
female/
7y
PBL de novo 47,XX,+mar[70%]/
46,XX[30%]
r(21)(::p11.2q21::) all available centromeric probes; wcp 21 see below {5} case 8  
slightly retarded development, flat root of nose, broad nose, wide mouth, dental anomalies, splayfoot, hypotonia of trunk
  21-W-
q21.?/
1-1 °
female/
3.5y
PBL de novo 47,XX,+r[56%]/
46,XX[44%]
?min(21)(:pterq21.?:)* midi; wcp probes for the acrocentric chromosomes see below {8}  
During pregnancy mother had taken multiple medications including synthroid and amphetamines; induced delivery at 36weeks due to maternal hypertension; weight 2,040g, OFC 31.5cm, APGAR 5/6/-;speech and motor delay at 3.5y; at this time height and weight at the 5th centile; OFC normal; long eyelashes, heavy eyebrows, wide-set eyes, protruding upper lip, autism suggested - no Down syndrome typical signs
  21-W-
q21.?/
1-2
female/
2.5y
PBL de novo 47,XX,+mar[100%] min(21)(pterq21~22.1:) centromeric probes, subcenM Down syndrome {0} provided by Dr. Ivan Iourov, Moscow, Russian Federation  
  ***
21-W-
q21.1/
1-1 °
***
n.a./
postnatal
PBL n.a. 47,+mar[75%]/
46[25%]
mar(21)(p?q21.1)*
size ~4.7 MB = position 18.1 MB
n.a. subcenM with 3 BACs, array CGH see below {19} case 25  
  Borderline normal intelligence with an IQ of 76; mild dysmorphic features; bipolar disorder with psychotic features; anxiety; diabetes mellitus, type 2; chronic enuresis; at 19 years of age, patient is taking general studies classes at a community college.  
  21-W-
q21.1/
1-2
female/
8y
PBL n.a. 47,XX,+mar[6]/
46,XX[47]

min(21)(pterq21.1)
size in q-arm 2.7 MB = position 15.9 MB

centromeric probes, subcenM;
aCGH
seizures, regression, MR {0} provided by Dr. Küchler, Essedn, Germany  
  21-W-
q21.1/
2-1 °
male/
2y
PBL de novo

47,XY,+mar[100%]

der(21)(pterq12:
:q21.2
p21.3:
)
aCGH: 21p11q21.1
(10,827,533-20,813,004)x3,
21q21.2q21.3
(25,913,510-30,831,133)x3

cep; subcenM;
aCGH
developmentally delayed - suggested for PWS {0} provided by Jasen Anderson, Brisbane, Australia  
  21-W-
q21.1~
21.2/
1-1
female/
4y
PBL de novo 47,XX,+mar[6]/
46,XX[15]
inv dup(21)(q21.1~21.2)
acc to aCGH: break in 30,868,226 MB - so in 21q22.11
acrocenM;
subcenM; LSI 21 (not present on sSMC)
aCGH
Down syndrome like phenotype {0} provided by Dr. Belitz, Berlin, Germany  
  21-W-
q21.1-q22.1/
1-1
female/
3y
PBL n.a. 47,XX,+mar[100%] der(21)(pterq21.1:
:q22.1pter)
aCGH;
subcenM
DD; minimal DYS; seizures {0} provided by Dr. Huhle, Leipzig, Germany
 
  21-W-
q21.3/
1-1
male/
9y
PBL de novo 47,XX,+mar[100%] min(21)(pterq21.3:) subcenM; LSI 21 (not present on sSMC) mental retardation, no DS {0} provided by Dr. Polityko, Minsk, Belarus  
  21-W-
q21.3/
1-2
female/
prenatal
AF n.a. 47,XX,+mar[?%]/
46,XX[?%]
mar(21)(pterq21.3:)* aCGH termination of pregnancy - no info available {34} case 19  
  21-W-
q21.3/
2-1
female/
11y
PBL n.a. 47,XX,+mar[6]/
46,XX[9]
inv dup(21)(q21.3)
arr[hg19] bp in q 31.98 Mb
subcenM;
aCGH
abnormal {0} provided by Dr. Kunz, Berlin, Germany  
  21-W-
q21~
22.1/
1-1
male/
1m
PBL maternal
in normal mother mar in 36/50 metaphases
47,XY,+mar[53]/
46,XY[12]
min(21)(pterq21~22.1:)* cep probes; wcp probes; probe in 21q22.2 newborn studied due to hypotonia but without other abnormal phenotypic features {11}  
  21-W-
22.1?1/
1-1
male/
2y
PBL de novo 47,XY,+mar[100%] min(21)(pterq21.1?1:) cep probes; wcp probes; probe in 21q22.2 see below {0} provided from Hungar  
  abnormal ears, hypertelorism, almond-shaped palpebral fissures, carp-shaped mouth, brachydacytly, delayed motor and speech development, muscular hypotonia, cryptorchism  
  21-W-
q22.13/
1-1
female/
prenatal
AF n.a. 47,XX,+mar[25%]/
46,XX[75%]
min(21)(:p12q22.13:)
array: 0.00-37.88 MB
midi, array-CGH Prenatal diagnosis due to advanced maternal age; pregnancy terminated due to phokomely of all 4 extremities {0} provided by Dr. Heilbronner, Stuttgart, Germany  
  21-W-
q22.3/
1-1
n.a./
prenatal
chord blood de novo 47,+mar[45]/
46[5]
inv dup(21)(p10) cep probes, wcp21 see below {14} case 20  
Amniocentesis due to advanced maternal age and ultrasound abnormalities: diaphragmic hernia, ascites, Dandy Walker anomaly
                     

 

W-Cases with similar imbalances NOT caused by sSMC (W-IMB):

 

 
  case no. gender/
age at diagnosis
studied
material
de novo/
inherited
GTG-banding result and FISH result incl. grade of mosaicism test
methods
clinical symptoms reference  
  21-W-
IMB-
q22.1/
1-1 to
1-3
see {25-27} {25-27}  
                   


W-cases with unclear/insufficient characterization of the sSMC (CW):

 

 
  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-
CW-1
male/
1y
PBL de novo 47,XY,+mar[50%]/
46,XY[50%]
del(21)(q?)* .ish D13/21Z1+,wcp21+ different FISH probes mild Down-syndrome features {2} case 8  
  21-
CW-2
female/
1m
PBL maternal (in 16/50 mitosis in mother) 47,XX,r(21),+mar[20%]/
46,XX,r21[?]/
45,XX,-21[?]
inv dup (21)(q1?)* .ish D13/21Z1++,wcp21+ different FISH probes see below {2} case 9  
pregnancy and delivery normal; weight 3080g; length 48cm; APGAR 4/8/9; asphyxia; facial dysmorphism like low forehead, antimongoloid slant of palpebral fissures, narrow lips, low set ears, microretrognatia,; large hands and irregularly inserted toes
                     

 


References

Cases with unclear clinical correlation (U)

 

 
  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
female/
prenatal
CH de novo 47,XX,+mar[9]/
46,XX[6]
min(21)
in later performed amniocentesis 47,XX,+21
different FISH probes:
D13/21Z1
CVS due to advanced  fetal nuchal translucency of 7.6 mm.
Down-Syndrome
{3} case 1  
  21-
U-2
male/
2.5y
PBL familial
maternal t(17;21)(p?;q?)
47,XY,+mar[100%] n.a. n.a. severe growth and mental retardation {4}  
  21-
U-3
male/
prenatal
AF de novo 47,XY,+r[32]/
46,XY[18]
r(21)(::p10q22.?::)* all available centromeric probes; wcp 21 Amniocentesis due to raised serum screen risk; pregnancy terminated {6} case 25  
  21-
U-4
male/
prenatal
AF/fetal tissue de novo 47,XY,+21[25]/
47,XY,+mar[34]/
46,XY[41]
min(21) .ish(wcp21+,cep13/21+) cep 13/21; wcp21 see below {9}  
Amniocentesis due to advanced  maternal age; termination of pregnancy as Down-syndrome mosaic symptoms were expected; post-mortem examination did not show any abnormalities
  21-
U-5
male/
prenatal
AF de novo
47,XY,+mar[100%]
min(21)(:p11.2q11.2:)[1]/
inv dup(:p11.1
q11.2:
:q11.2
p11.1:)[1]/
dic(21)(:q11.2
p11.1:
:q11.2
p11.1:)[3]/
dic(21)(:p11.1
q11.1:
:p11.1
q11.2:)[2]
cenM/
subcenM
Prenatal diagnosis. Indication was a previous pregnancy with triploidy. No echographic indication and no follow-up available. {0} provided by Dr. J. Vermeesch, Leuven, Belgium  
  21-
U-6
see mult 2-21
{15} case NP
{16} case 16
 
  21-
U-7
male/
12y
PBL maternal t(7;21) 47,XY,+mar[100%] der(21)t(7; 21)(p21;q21.3) FISH different probes acc to {17} see below {17; 39}  
Born at term after normal pregnancy. Birth weight 4010 g, length 50 cm head circumference 35 cm. Pneumonia and septicemia complicated the neonatal period. At 4 months infantile spasm. Encephalographic investigations showed hypsarrhythmia. Two hypopigmented spots on the skin, positive to Wood's light, aroused suspicion of tuberous sclerosis. Computerized tomography of the brain showed mild to moderate central and cortical atrophy. On this basis, tuberous sclerosis was excluded as a possible diagnosis. Repeated upper respiratory tract infections and otitis, suffered from constipation, and severe feeding problems. Psychomotor development severely retarded. He sat without support first at 14 months and was not able to walk until age 6 years and 6 months. At 12y unable to speak or to use sign language. He is autistic, which was obvious already before the age of 1 year. At 8 years -  height 111 cm (<-3 S.D.), weight 20 kg (-2 S.D.) and head circumference 51.5 cm. (+0 S.D.). He did not resemble the other members of his family. He had a prominent forehead, down slanted palpebral fissures and hypertelorism. Strabismus was noted and he had mild hyperopia. He had a high and broad nasal bridge, a broad nose, a prominent philtrum, a large mouth, prominent lips and down-turned corners of the mouth. The palate was short and narrow. He had micrognathia, prognathism, low-set, dysplastic and posteriorly rotated ears and narrow ear canals. He had mild muscular hypotonia, hyperextensibility of joints, pes calcaneo-valgus, brachydacyly and single transverse palmar crease unilaterally.
  21-
U-8
male/
prenatal
AF de novo 47,XY,+mar[100%] min(21)(pter→q21.1:)*
distal marker on sSMC RP11-143A3 (18.24 MB)
array CGH FISH Amniocentesis due to abnormal ultrasound findings and advanced maternal age; child born; no info available {18} case 3
{29}case 5
 
  21-
U-9
female/
prenatal
AF de novo 47,XX,+mar[50%]/
46,XX[50%]
min(21)(pter→q11.2~21.1:) cenM; subcenM; LSI 21 advanced maternal age; plexus cysts; TOP; in autopsy normal apart from hypertelorism {0} provided by Dr. Altus, Magdeburg, Germany  
  21-
U-10
female/
13y
PBL n.a. 47,XX,+mar[8]/
46,XX[22]
min(21)(pterq11.2~21.1:) cep probes; subcenM; LSI 21 n.a. {0} provided by Dr. Prager/ Junge, Dresden, Germany  
  21-
U-11
female/
prenatal
AF/PBL de novo 47,XX,del(21(q22),+mar[22]/
46,XX,del(21)(q22)[7]/
46,XX,-21,+mar[5]/
45,XX,-21[4]
min(21)(pterq11.2:) FISH with LSI 21 and AML1; array-CGH see below {31}  
Amniocentesis due to advanced maternal age; at birth lenght 46 cm (-2.74 SD), weight 2240 g (-4.4 SD), head circumference 31 cm (-3.16 SD). APGAR scores 1/8/9. High nasal root, downslanting palpebral fissures, retrogenia, posterior rotated, slightly low-set ears, a long philtrum, and a thin upper vermillion were noticed. The fingernails were small. A sacral dimple was observed. Cerebral ultrasound showed a missing septum pellucidum. Major problem was feeding, most probably due to sucking weakness and a lack of coordination so that a feeding tube had to be placed.
  21-
U-11
female/
prenatal
AF de novo 47,XX,+mar[100%] min(21)(pterq11.2:) ceps, BACs and MLPA advanced maternal age; normal sonography, TOP {32}  
  21-
U-12
female/
prenatal
AF de novo 47,XX,+mar[13]/
46,XX[6]
min(21)(pterq11.2~21:) cenM, subcenM, LSI 21 (not on sSMC) advanced maternal age; lost during follow-up {0} provided by Dr. Schliephagen, Linden, Germany  
  21-
U-13
female/
11y
PBL n.a. 47,XX,+r[100%] r(21) SKY dermatitis, acquired acanthosis nigricans {36} case F067630
 
  21-
U-14
female/
prenatal
AF n.a. 47,XX,+mar[100%] min(21)(pterq11.2:) cenM, subcenM advanced maternal age; {0} provided by Dr. Wegner, Berlin, Germany
 
  21-
U-15
female/
2 y
PBL maternal
t(4;21)
47,XX,+mar[100%] der(22)t(4;21)(q32.1;q21.2) aCGH MR, DD, facial abnormal, {39}
 
  21-
U-16
n.a./
prenatal
AF maternal
t(4;21)
47,XN,+mar[100%] der(22)t(4;21)(q35.2;p11.2) aCGH n.a {41}  
  21-
U-17
female/
prenatal
AF n.a. 47,XX,+mar[100%] mar(21)(q11.2q21.1) arr[hg19]15.48-21.70 Mb aCGH n.a. {0} provided from Portugal
 
  21-
U-18
male/
prenatal
AF n.a. 47,XY,+mar[60%]/
46,XY[40%]
del(21)(q11.2) or min(21)(:p11.2->q11.2)

cenM;
subcenM

AMA {0} provided by Dr. Bartels, Göttingen, Germany  
                     

 

case with constitutional 46,XX,r(21)(pter→q22): developing an AML with amplification of AML1 gene located in 21q22

Streubel B, Valent P, Lechner K, Fonatsch C.
Amplification of the AML1(CBFA2) gene on ring chromosomes in a patient with acute myeloid leukemia and a constitutional ring chromosome 21.Cancer Genet Cytogenet.
2001, 124:42-46.

 


References

Cases with neocentromeres (N)

 

1 neocentromere 21 case (no sSMC):

Barbi G, Kennerknecht I, Wohr G, Avramopoulos D, Karadima G, Petersen MB.
Mirror-symmetric duplicated chromosome 21q with minor proximal deletion, and with neocentromere in a child without the classical Down syndrome phenotype.
Am J Med Genet. 2000 Mar 13;91(2):116-122.

 

N-Cases with similar imbalances NOT caused by sSMC (N-IMB):

 

 
  case no. gender/
age at diagnosis
studied
material
de novo/
inherited
GTG-banding result and FISH result incl. grade of mosaicism test
methods
clinical symptoms reference  
  21-N-
IMB-
p10/
1-1
male/
newborn
PBL de novo 47,XX,+inv dup(21)(p11.1) wcp 12, 21 see below {20}  
neonate revealed similarities to Down syndrome  
  21-N-
IMB-
p10/
1-2
see above - similar case {23} case 17  
  21-N-
IMB-
p10/
1-3
see above - similar case {30} case 23  
  21-N-
IMB-
qter/
1-1 to
mult
see {28} {28}