The frequent and clinically benign anomalies of chromosomes 7 and 20 in Shwachman-diamond syndrome may be subject to further clonal variations

Table 2 Patients with del(20)(q) as sole anomaly in BM: definition of the deletion by a-CGH (patients 1–8) or FISH (patients 11 and 12)

Patient	Bands	Deletion start (bp)	Deletion stop (bp)	% Abnormal cells
1	q11.21-q13.13	31,954,597	48,328,296	36%
3	q11.2-q13.2	31,720,622	53,559,811	26%
5	q11.21-q13.13	30,849,566	49,398,586	29%
6	q11.21-q13.13	30,889,915	47,912,299	74%
7	q11.21-q13.13	31,412,080	49,339,757	39%
8	q11.21-q13.32	31,671,222	57,911,624	36%
11	q11.22-q12^a	–	–	5.6%^b
12	q11.22-q12^a	–	–	2.9%^c

The percentage of abnormal cells is calculated from a-CGH results, except for patients 11 and 12
^aResult obtained by double color FISH with the bac probes RP11-17F3 and RP11-29E13: the deletion therefore is at least from 33,797,020 to 40,857,566 bp
^b% from FISH results: 1/16 mitoses and 18/321 nuclei
^c% from FISH result: 9/309 nuclei

ISSN: 1755-8166