TL

ChromosOmics - Database

Icon by Leon Liehr

- CHROMOSOME #21 -
NEOCENTRIC

Cases without clinical findings	Similar imbalances – no sSMC
Cases with clinical findings	Similar imbalances – no sSMC
Cases without clear clinical correlation	Cases with discontinous sSMC
Cases with complex sSMC	Cases with UPD and sSMC
Cases with neocentromeres	Similar imbalances - no sSMC
Tumor	DISCLAIMER

References

In general 70% of sSMC carriers are clinically normal. The figures listed above

are based on the bias, that mainly clinically aberrant cases are studied and reported in literature!

UPD (uniparental disomy) cases:

UPD(21)mat

UPD(21)pat

UPD(21)mat or pat

Cases with neocentromeres (N)

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- N- p or q/ 1-1	-	-	-	-	-	-	-	-

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.

Cases with neocentromeres (N) - TUMOR

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- N- p or q/ 1-1	-	-	-	-	-	-	-	-

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

case no.	gender/ age at diagnosis	studied material	de novo/ inherited	GTG-banding and final FISH result	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	neonate revealed similarities to Down syndrome	{20}
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}
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