ChromosOmics - Database
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             sSMC formed by McClintock-mechanism  -          
START

by chromosomal origin for sSMC formed by McClintock mechanism
sSMC
1

sSMC
2

sSMC
3

sSMC
4
sSMC
5

sSMC
6

sSMC
7

sSMC
8
sSMC
9

sSMC
10
sSMC
11

sSMC
12

sSMC
13

sSMC
14

sSMC
15

sSMC
16

sSMC
17

sSMC
18
sSMC
19

sSMC
20
sSMC
21
sSMC
22

sSMC
X

sSMC
Y
DISCLAIMER
References

"In one of her seminal contributions Barbara McClintock describes the mechanism leading to the formation of ring/deleted chromosomes in maize and the aberrant mitotic behaviour leading to 'variable mutant characteristics'. This mechanism, a break within the centromere together with a break in either the long or the short arm, creating a small ring, has been called "centromere misdivision"; these authors propose that this be referred to as "the McClintock mechanism". McClintock also describes pachytene configurations in microsporocytes, showing that although the normal, deleted and ring chromosomes may synapse, the ring is also seen with the centromeric region attached to a non-homologous bivalent."
(cited from
Mantzouratou et al., Molecular Cytogenetics 2009, 2:3)

by chromosomal origin for sSMC formed by pseudo-McClintock mechanism


However, it turned out that similar to McClintock mechanism with ring chromosome formation, there are cases which seem to evolve by a related mechnaism, called pseudo-McClintock mechansim.
sSMC McClintock mechanism - ring chromosome formation

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
Neocentric/ healthy

McCl-
01-
N-
p32/

1-1
male/
38y
PBL/
fibro-
blasts

n.a.
47,XY,del(1)(p32p36.1),
+mar1[87]/
47,XY,del(1)(p32p36.1),
+mar2[10]/
46,XY,del(1)(p32p36.1)[3]
(fibroblasts: 95/5/0; plus a t(X;4)(q23;q13))

mar1 = r(1)(::p32p36.1::)/
mar2 = r(1)(::p32
p36.1: :p23p36.1::)
pan-centromeric probe, telomeric probe, wcp1 probe; UPD-test infertility and oligospermia; otherwise normal male {1-5; 58}
Neocentric/ healthy

McCl-
01-
N-
p21/
1-1
n.a./
postnatal
PBL n.a.
47,XN,del(1)(p21p13),+mar
r(1)(::p21p13::) FISH n.a., presumably normal {59} 1 case
Healthy

McCl-

01-
N-
p13/
1-1
male/
39y
PBL n.a. 47,XY,del(1)(p13p11.1),
+mar[100%]
r(1)(::p13p11.1::)
M-FISH; MCB, ceps
normal male, infertile
{70} case 1
Neocentric/ unclear

McCl-

01-
N-
q23/
1-1
male/
prenatal
AF de novo 47,XY,del(1)(q23q32),
+mar[20]
r(1)(::q23q32::)
"dynamic mosaic" i.e. variants of sSMC were detected but not characterized in detail
wcp1; cep1/5/19; all centromere probe Amniocentesis due to advanced maternal age; no ultrasound abnormalities; pregnancy terminated. {3-6}
Healthy

McCl-

02-
O-
p12/

1-1
male/
adult
PBL de novo 47,XY,del(2)(p12p11.1),
+mar[100%]*
r(2)(::p12p11.1::)
FISH-data: RP11-316G9 = AC009958.3 (89.6 MB) and RP11-294I29 = AQ508381 (88.9MB) on sSMC
cen2, wcp2, YACs as specified in {11} Man was studied due to a child with a phenotype resembling Down-syndrome; child had karyotype 46,XY,del(2)(p10p12) {0}
{8}
Neocentric/ abnormal

McCl-

02-
N-
p21/

1-1
male/
14y
PBL de novo 47,XY,del(2)(p21p11),
+mar[100%]
r(2)(::p21p11::) wcp2, pan-centromeric probe; telomeric probe moderately mental retarded, at 32y weight and OFC at 25. centile; narrow forehead, broad supraorbital ridges, large mouth, marked hyperkyphosis, moderately hyperactive, IQ = 50
{3; 9-11}
Neocentric/ abnormal

McCl-
02-
N-
q22/

1-1
female/
postnatal
PBL
(EKF-
cellbank)
n.a. 47,XX,del(2)(q22q32.2),
+r(2)(q22q32.2)[81]/
46,XX,
del(2)(q22q32.2)[9]
r(2)(::q22q32.2::) midi mental retardation {12} 1 case
Abnormal

McCl-

03-
W-
p11/

1-1
male/
26y
PBL/
fibro-
blasts
de novo 47,XY,del(3)(p11q11),
+mar[28]/
46,XY,del(3)(p11q11)[12]
mar present in 100% of skin fibroblasts
min(3)(:p11q11:)
Neocentromere formation in 3q26 on del(3) chromosome.
wcp3; cep3 The male was considered to have borderline mental retardation, and was detected due to his newborn daughter with developmental delay, hypertelorism, epicanthus. She inherited only the del(3) chromosome.
{13; 14; 15 case 1}
Neocentric/ normal

McCl-

04-
W-
p16.1/

1-1
male/
42y
PBL n.a. 47,XY,+mar[3]/
46,XY[14]
r(4)(::p16.1p14:)
Neocentromere formation in 3q26 on del(3) chromosome.
midi normal male, prinary infertility
{0, 67} case P3
Abnormal

McCl-

04-
W-
p15.3/

1-1
male/
prenatal
AF de novo 47,XY,
del(4)(p15.3q21.1),
+r[96]/
46,XY,del(4)(p15.3q21.1)[4]
r(4)(::p15.3q21.1::) cep 4, sub-telomeric probe 4q; WHS probe see below {16}
Amniocentesis due to ultrasound detection of advanced nuchal translucency, echogenic bowel, short femurs, mild ventricular dilatation; IUGR at 5. centile; at week 32 oligohydramnion; at week 33 no fetal movements and intrauterine death confirmed at week 34; on delivery bay 640g ([lt]0.4 centile) and macerated; detectable were anal atresia, neck webbing, umbilical cord with two vessels
Healthy

McCl-

04-
W-
p12/

1-1
female/
adult
PBL n.a.; same mar imbalanced in child 47,XX,+mar[67%]/
46,XX[33%]
47,XX,del(4)(p12q10),
+r(4)(::p12q10::)[66%]/
46,XX,del(4)(p12q10)[33%]
*
size 4.4 MB
centr. probes, centr.-near probes; aCGH child with mild speech delay; no dysmorphic features; normal motor development; Mother is intellectually normal with unilateral ear anomalies and mild visual deficiencies. {17}
{18} case 7
Unclear

McCl-

04-W-
q10/

1-1
female/
prenatal
AF de novo 47,XX,+mar[9]/
46,XX[5]
47,XX,del(4)(q11q13),
+r(4)(::q11q13::)[66%]/
46,XX,del(4)(q11q13)[33%]
*
size 22 MB
aCGH advanced maternal age; TOP {60}
Neocentric/ abnormal

McCl-

04-W-
q12/

1-1
male/
6m
PBL de novo 47,XY,del(4)(q12q21.1)+mar[5]/
46,XX,del(4)(q12q21.1)[25]

+r(4)(::q12q21.1::)
arr(hg19):
56,288,188-77,876,928
aCGH DYS, skin pigmentaton, DD, growth delay
{66}
Neocentric/ abnormal

McCl-

04-
N-
q22.1/

1-1
male/
17y
PBL/
fibro-
blasts
de novo 47,XY,del(4)(q21.1q21.3),
+mar[75%]/
46,XY,del(4)(q21.1q21.3)[25%]*
r(4)(::q21.1q21.3::)*
sSMC derived from maternal chromosome 4
midi; telomeric probes, YACs; UPD-test neonatal eczema, multiple infections; studied due to Hyper-IGE syndrome with recurrent infections (HIES); motor, language, social and developmental milestones of patient delayed; mother of patient borderline to mental retardation, autism {19; 3-5}
Neocentric/ abnormal

McCl-

04-
N-
q26/

1-1
female/
prenatal

AF
NIPT

n.a. 47,XX,+mar[23]/
46,XX[21]

r(4)(::q26q31.21::)*
NIPT VSD; no further info available
{71} case SJ015
Abnormal

McCl-

0
5-
W-
p13/

1-1

male/
27y
PBL n.a. 47,XY,del(5)(p13q10),
+r[68]/
46,XY,del(5)(p13cen)[2]
r(5)(::p13q10:
:p13
q10::)
cep 1/5/19; YAC 897G2 see below {20}
Birth weight 3500g (50th centile), OFC 38cm (>95. centile); length 50cm (25. centile); square asymmetric skull, plagioturricephaly, facial asymmetry, hypertelorism, epicantal folds, short and broad nose, long, deep philtrum, microretrognathism, high palate, low-set abnormal ears, clinodactyly 5, simian crease, hypotonia, omphalocoele, inguinal hernias, club feet; at 20m weight at 90. centile OFC >97. psychomotor development delayed.
Healthy

McCl-

05-
W-
p11/

1-1
male/
prenatal
AF,
PBL
de novo 47,XY,del(5)(p11p13),
+mar[100%]
after array: 47,XY,der(5)(pter→p15.31:
:pter→p14.3::p11→qter),
+r(5)(::p11→q13.2::)
r(5)(::p11q13.2::)
array: 5p15.33-p15.31 (131,945-6,267,160)x3, 5p14.3-p13.2 (21,438,495-
36,736,934)x1,
5p12-p11 (42,529,343-
45,908,725)x3
BAC-FISH, aCGH amniocentesis due to advanced maternal age; normal male at birth and at 1.5y {54}
Healthy

McCl-

06-
O-
p22.3/

1-1
male/
43y
PBL n.a. 47,XY,del(6)(p10p22.3),
+r(6)(::p10→p22.3::)[100%]
r(6)(::p22.3q10::)* wcp6, cep 6, subtel 6p and 6q normal male apart from infertility {21}
{22} case 10
Healthy

McCl-
06-
O-
p11.2~
p11.1/

1-1
female/
37y
PBL de novo 47,XX,del(6)(p11.2~p11.1q12),
+r(?6)[80%]/
46,XX[20%]
r(6)(::p10q12::)[60%]/
r(6)(::p11.2~p11.1

q12::)[20%]
midi/
subcenM
normal, but two abnormal children with mar {58}
Healthy

McCl-
06-
O-
p10/

1-1

female/
30y
PBL n.a. 47,XX,del(6)(p10q13),
+r(6)[?%]/
46,XX[?%]
r(6)(::p10q13::)
array: 77.23-96.63MB
MCB, aCGH normal, but one abnormal children with mar {55} mother of patient 2
Neocentric/ healthy

McCl-

06-
N-
q16.2/

1-1
male/
adult
PBL de novo? 47,XY,t(4;15),del(6)(q16.2q22.2),
+r(6)(::q16.2→q22.2::)[100%]
r(6)(::q16.2q22.2::)

all centromeres, wcp probes, sub-telomere 6q
mar detected due to phenotypically abnormal child of propositus; child had karyotype 46,t(4;15),del(6)(q16.2q22.2)[100%] {5; 23-24}
Abnormal

McCl-
07-
N-
p22/
1-1

male/
2y
PBL de novo 47,XY,del(7)(p22q21.2),+ r(7)(p22q21.2)
cep 7 DD, DYS, growth retardation {62}
Neocentric/ abnormal

McCl-
07-
N-
q22/
1-1
male/
newborn
AF/
PBL
de novo AF: 47,XY,+r(7)(q22q31)[10]/46,XY[7]
PBL: sSMC only in 28% of cells
unusual complex McClintock mechanism
r(7)(q22q31) M-FISH
aCGH
DD, DYS, growth retardation, MR {63}
Healthy

McCl-

08-
O-
p11.1/

1-1
male/
adult
PBL de novo 47,XY,del(8)(p11.1q12.1),+r(8)(p11.1q12.1)[18]/
46,XY[2]
r(8)(::p11.1q12.1::)*
neocentromere in 8p22 in der(8)
aCGH, cep 8
normal male, sSMC detected due to child with clinical abnormalities due to lacking sSMC
{25; 53; 58}
Healthy

McCl-

08-
O-
p11.1/

2-1
male/
adult
PBL n.a. 47,XY,del(8)(p23q10),+r(8)(p23q10)[55]/46,XY,del(8)(p23q10)[5] r(8)(::p23q10::)
NGS, cep 8 infertile {65} case 1
Neocentric/ abnormal

McCl-

09-
N-
q31/

1-1
female/
adult
PBL n.a. 47,XX,del(9)(q31q33),+r(9)(q31q33)[60%]/
46,XX,del(9)(q31q33)[40%]
r(9)(::q31q33::) aCGH; BAC FISH mild degree of mental retardation (IQ 69); sSMC detected due to child with a 46,XY,del(9)(q31q33)[100%] and mild psychomotor retardation {30}
Unclear

McCl-
09-
N-
q10/
1-1
female/
?adult
PBL n.a. 47,XX,del(9)(q10porq?),+r(9)(q10porq?) n.a. wcp 9 mental retardation {56}
Abnormal

McCl-

10-
W-
p11.23/

1-1
male/
4y10m
PBL inv dup (13 or 21) paternal derived
48,XY,del(10),+r(?10),
+inv dup(acro)[100%]
double rings in 4-8% of the cells
del(10) = der(10)(pterp11.23:
:q23.2
qter)
r(?10) = r(10)
(::p11.23q23.2::)
inv dup(acro) = inv dup(13o
r 21)
cep10, 13/21; 14/22; 15; 5 different alpha sat.- probes; satIII probe developmental delay at 4y, delayed speech development, normal motor activity, not dysmorphic; height, length and HC ~25. centile {3-4; 10; 31-39}
Neocentric/ abnormal

McCl-

10-
N-
q11/

1-1
female/
1w

AF/
fibro-
blasts
de novo 47,XX,del(10)(q11q23),+mar[62%]/
46,XX,del(10)(q11q23)[38%]
(sSMC in 80% of fibroblasts)
?min(10)(:q11q23:)
(without detectable telomeres)
alpha-, beta-satellite satIII,telomeric, all wcp, YAC-probes (not specified) mental retardation and/or developmental delay or structural anomalies detected at birth {26} case 8
{3-5, 10}
Abnormal

McCl-

11-O-
p15.1/

1-1
female/
newborn
PBL
fibro-
blasts
maternal PBL: 47,XX,del(11)(p11.1p15.1),
+r(11)(p11.1p15.1)[70%]/
46,XX,del(11)(p11.1p15.1)[30%]
In fibroblasts: marker in 50%
r(11)(::p11.1p15.1::)* cep 11 severely dysmorphic; Turner-like phenotype with classical bilateral aniridia, microcephaly, Fallot tetralogy; mother with aniridia as well - here mar in 70% of the blood cells; otherwise normal {40}
Neocentric/ abnormal

McCl-

11-
N-
p11.2/

1-1
female/
adult
PBL n.a. 47,XX,del(11)(p11.12p11.2),+mar[100%] r(11)(::p11.12p11.2::) n.a. normal - sSMC detected due to clinical abnormalities in a child {5; 7}
Neocentric/ abnormal

McCl-

11-
N-
q21/

1-1
male/
newborn
PBL
fibros
de novo
47,XX,del(11)(q21),+mar[100%] inv dup(11)(q21) n.a. DD; MR, DYS
{68}
Unclear

McCl-

12-
U
p13.1/
1-1
female/
3m
PBL maternal 47,XX,del(12)(p13.1→q10),+r[100%] r(12)(::p13.1q10::) wcp12 mother normal?; child? {27}
Unclear

McCl-
13/21-‘
U-
p11.1/
1-1
see 13/21-U-4 - similar to a McClintock mechanism, but not the same
Neocentric/ healthy

McCl-

13-
N-
q12.3/

1-1
male/
29y
PBL n.a. 47,XX,del(13)(q12.3q22),
+mar[97]/46,XX,del(13)(q12.3q22)[3]
r(13)(::q12.3q22::) wcp, array-CGH normal male; fertility problems {51; 57; 58}
Neocentric/ healthy

McCl-

13-
N-
q21.31/

1-1
female/
32y
PBL de novo 47,XX,del(13)(q21.32q22.2),
+mar[100%]
r(13)(::q21.31q22.2::) midi; telomeric probe normal female; sSMC detected due to 3 miscarriages {4-5, 29-30; 42}
Neocentric/ abnormal

McCl-

13-
N-
q31.1/

1-1
male/
1m (?)
PBL de novo 47,XY,del(13)(q31.1q32.3),
+r(13)(::q31.1q32.3::)[50%]/
46,XY,del(13)(q31.1q32.3)[50%]
r(13)(::q31.1q32.3::) BAC-probes moderate intellectual disability associated with distinctive hand malformations (hypoplastic and angel-shaped middle phalanges) and partial growth hormone (GH) deficiency at 13 y {5; 28}
Neocentric/ abnormal

McCl-
14-
N-
q12/
1-1
female/
18y
PBL n.a. 47,XX,del(14)(q12q24.3),
 +r(14)(q12q24.3)
r(14)(::q12q24.3::) sequencing;
FISH
MR, DD, tetraplegia, osteoporosis, no speach, seizures, DYS {61}
Neocentric/ healthy

McCl-
15-
N-
q11.1/
1-1
male/
14y
PBL n.a. 47,XY,del(15)(q11.1q21.1),
+r(15)(q11.1q21.1)
r(15)(::q11.2q21.1::) FISH Marfan syndrome like
infertile
{64}
Neocentric/ unclear

McCl-
15-
N-
q11.1/
2-1
female/
prenatal
CH, AF
de novo
47,XX,+21[12]/
48,XX,+21,+mar[3]
r(15)(::q25.2q25.3:) aCGH Down syndrome,. TOP
{69}
Abnormal

McCl-

16-
W-
p10/

1-1
female/
23y
PBL n.a. 47,XX,del(16)(p10q13), +r(16)(::p10→q13::)[100%]* r(16)(::p10q13::) n.a. mild general hypotonia, HC 51cm = very small; bow shaped mouth, abnormal posteriorly rotated ears; apart from that normal; detected due to a malformed child without the mar but with the del(16) chromosome {43}
Abnormal

McCl-

16-
W-
q13/

1-1
male/
8y
PBL n.a. 47,XX,del(16)(q13q23), +r(16)(::q13→q23::)[100%]* r(16)(::q13q23::) aCGH, MCB
short stature, speech delay {70} case 5
Healthy

McCl-

17-
O-
p11.2/

1-1
moved to PsMcCl-17-O-p11.2/1-1
Healthy

McCl-

17-
U-
p10/
1-1
female/
82y

PBL
skin
fibro-
blasts
de novo 48,XX,del(17)(p10q11.2),+r[2%]/ 47,XX,del(17)(p10q11.2),+r[~75%]/ 47,XX,del(17)(p10q11.2),+r(dic)[12%]/ 47,XX,del(17)(p10q11.2),+mar[~5%]/
46,XX,del(17)(p10q11.2)[6%]*

similar in blood and fibroblasts;
marker derived from (17)(p10q11.2) centromeric probe for chromosome 17 no congenital malformations; suffering from neurofibromatosis type 1 since age of 40y; neither her parents nor her children had NF1. Children with normal karyotypes. {47}
Abnormal

McCl-

19-
W-
p10/

1-1
male/
1m(?)
PBL maternal 47,XX,del(19) (p10q13.2),+r(19) 47,XY,+r[100%] r(19)(::p10q13.2::)* FISH probe wcp 19 see below {48}
Delivery in week 37 because of maternal blood hypertension; birth weight 2280g; overweight syndrome at 3-4y → every mensurartions were more than 3S.D. except for the length. Additionally macrocephaly, hypertelorism, antimongoloid slants, bluish ring around the eyes, globular prominent nose, abnormal mouth, large ears, arms and legs short and podgy, mental retardation (DQ=69)
Healthy

McCl-

22-
O-
q11.1/

1-1
female/
44y
PBL n.a. 47,XX,del(22)(p11.1q11.2)
+mar[16]/
46,XX,del(22)(p11.1q11.2)
r(22)(::q10q11.2::) DiGeorge CR-probe; array-CGH normal female; mar detected due to repeated children with heart defects {52; 58}
Abnormal

McCl-

22-
W-
q11.2/

2-1
male/
infant
PBL maternal
47,XX,del(22)(q11q11.2),
+r(22)(q10q11.2)
47,XY,+mar[100%] r(22)(::q10q11.2::) cep probes; TUPLE1 probe CHARGE association {49}
Abnormal

McCl-

0X-
W-
p21/

2-1
female/
1y
PBL de novo 47,X,del(Xq),+r[20%]/
46,X,del(Xq)[80%]
in fibroblasts. 40/10
del(X) = der(X)(pterq21.1:
:p21
pter)
r = r(X)(::p21

q11~12::)
cep X; wcp X; pericentric probes; STS, KAL; UBE1XIST specific probe see below {50}
pregnancy and birth normal; birth weight 30. centile; length 10. centile; OFC 25. centile; syndactyly of right finger 3 and 4 and left toes 4 and 5; cardiac murmur due to ventricular and artrial septal defect and patent ductus arteriousus plus pulmonary stenosis; agenesis of corpus callosum, mild cerebral ventricular dilatation; a t 1y severely handicapped, no speech, hypotonia, broad face, short neck, prominent forehead, telecanthus, convergent strabismus, small abnormal nose, prominent inverted V-shaped upper lip, short philtrum, low set and mildly posteriorly rotated ears
Abnormal

McCl-

0X-
W-
q27.1/

1-1
male/
4.5y
PBL n.a. 47,XY,+mar[35]/
46,XY
r(X)(q27.1q28) aCGH see below {0} provided by family
in sonography enhanced nuchal transluciency; born normal; at 2 months reflux, at 6 months growth retardation (lenght 0.4th centile), DD, i.e. crawling with 20 months, walking at 2 years; at 4.5 years only 2 word sentences; slight dysmorphism; small head, hypogonadotropic hypogonadism; now under groth hormons.       
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