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Table 1 Cytogenetic finding and clinical data in 5 prenatal cases with a supernumerary der(20).

From: Characterization of a prenatally assessed de novo supernumerary minute ring chromosome 20 in a phenotypically normal male

Case Age Karyotype Cell system Mosaic finding in % Clinical finding Reference
1 8 months 46,XY/47,XY, +r(20)(::p12.2~12.3->q11.::)/
47,XY, +r(20)(::p12.1->
q11.1::q11.1->p12.1.::)/
47,XY,+min(20)(:p12.1->
q11.1::q11.1->p12.1:) de novo
Amnyocytes
(75:25%)
Normal psychomotor development Present investigation
2 20 months 46,XY/47,XY,+r(20 de novo Amniocytes (20:80%)
Cord bllod (91:9%)
Normal psychomotor development Viersbach et al 1997
3 20 months 46,XY/47,XY,+der(20 de novo Amniocytes (20:80%) Normal psychomotor development Viersbach et al 1997
4 16 months 46,XY,/47,XY, +r(20)/47,XY,+20/48,XY,+2r(20) Amniocytes
(10,5:44,7:44,7:0%)
Chorionic villi
(5,5:16,5:78,0:0%)
Amnion
(0:36,0:64,0:0%)
Skin
(16,7:80,6:1,6:1,1%)
Cord blood
(13,7:86,3:0:0%)
Delayed psychomotor development, height and below 3rd centile, hypotonia, asymmectric triangular face, prominent forehead, bulbous nose with slightly upturned tip, hypoplastic short philtrum, small mouth, high palate, micro- and retrognathia, abnormal ears, proximally placed adducted thumbs, clinodactyly lymphedema on the dorsa of feet, abnormal position of toes, prominent heels, increased skin elasticity, hyperextensible joints Batista et al 1995
5 6 months 46,XY/47,XY,+der(20) de novo Amniocytes
(75:15%)
Normal psychomotor development Cotter et al 2005