Nullisomic pattern. The patient shows four EcoRI bands after p13E-11 hybridization and none after double digestion with EcoRI/BlnI (nulisomic pattern). After hybridization with KpnI probe two BlnI resistant band are visible (45 and 20 kb): we can not guess the chromosomal origin of these alleles. To resolve the structure of the alleles we digested the sample with XapI enzyme which cuts the 4q-type repeats only (see Methods). After hybridization with p13E-11 we observed 4 XapI-resistant bands (38, 32, 13 and 8 kb): the 38 and 32 kb bands correspond to the EcoRI fragments of 42 and 36 kb fragments (XapI fragments are 4 kb smaller than EcoRI fragments). On the contrary the 13 and 8 kb fragments are stretches of the hybrid 4q alleles: the 62 kb EcoRI allele is composed by a BlnI-sensitive fragment (XapI-resistant) of 13 kb and a BlnI-resistant fragment of 45 kb (13+45 = 58 kb). The 32 kb EcoRI allele is composed by a BlnI-sensitive fragment (XapI-resistant) of 8 kb and a BlnI-resistant fragment of 20 kb (8+20 = 28 kb). The 4q variant alleles are represented in figure 5 (n.15 and 16). The FSHD 4q allele of 32 kb segregated also in other affected members of the family and its origin was confirmed by D4S139 probe (data not shown). * aspecific bands.
Rossi et al. BMC Medical Genetics 2007 8:8 doi:10.1186/1471-2350-8-8