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

Table 1 Patients with more than one clonal anomaly in BM, either in the same sample or in samples drawn in different years

Patient	Sample	Anomaly 1st clone—bands and DNA bp (% cells)	Anomaly 2nd clone—bands and DNA bp (% cells)
2	2009	del(20)(q11.21q13.13) 30,733,183–49,339,757 bp (43%)	del(20)(q11.22q11.23) 33,148,327–36,779,644 bp (23%)^a
4	2010	del(20)(q11.21q13.13) 31,954,597–49,216,901 bp (17%)^b dup(20)(q13.32–q13.33) 58,349,436–60,320,956 bp (19%)^b	dup(3)(q24q29) 143,044,212–195,076,511 bp (34%)^b
9	2009	del(20)(q11.21q13.32) 30,876,455–57,739,561 bp (55%)	–
9	2017	–	del(20)(q11.21q13.13) 30,904,022–49,344,382 bp (52%)
10	2009	i(7)(q10) (24%)^c	–
10	2017	i(7)(q10) (16%)^c,d	del(7)(p21.3pter) (10%)^d
13	2018	del(20)(q11.22q11.23) 32,738,995–34,468,385 bp (35%)	del(20)(q11.2q13)^e 2 out of 6 mitoses
14	2017	del(20)(q11.21q12) 31,814,242–40,237,993 bp (12%)^b dup(20)(q11.33) 58,725,726–61,314,465 bp (18%)^b	–
14	2019	del(20)(q)^f	del(20)(q)^f

Chromosomal anomalies were defined by a-CGH except where noted otherwise. The percentage of abnormal cells is calculated from a-CGH results, except for the 2^nd clone of patient 13 and the 2019 sample of patient 14
^aThis percentage refers only to the 2nd clone ^b The anomalies may be in independent clones or associated in a single clone
^ca-CGH results showed monosomy of the entire short arm and trisomy of the entire long arm
^dThe anomalies were in two independent clones, as shown by FISH (Fig. 1c, d, e)
^eResult of chromosome analysis
^fTwo clones with different del(20)(q), as shown by double color FISH with two different probes identifying different regions of chromosome 20 long arm (Fig. 3 D)

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