Inositide-specific phospholipase c β 1 gene deletion is a rare event in myelodysplastic syndromes

In their letter,1 commenting to our paper,2 Lo Vasco et al. precise the prognostic data of the MDS patients included in their original paper3 on cryptic deletions of the inositide-specific phospholipase c 1 gene (PI-PLC 1). All the patients with MDS and a normal karyotype at diagnosis were at high risk as evaluated by clinical meanings (French-American-British classification (FAB), International Prognostic Scoring System (IPSS)). In our series,2 selection of the patients was done according to the unique criteria given by Lo Vasco et al. in their original paper,3 that is, the evidence of a normal karyotype at diagnosis. The IPSS score in our cases was low (12 patients), intermediate (10) or high (1). The discrepancies between the results of both studies probably can be explained by differences in the selection of the MDS populations. The data of Lo Vasco,1, 3 strictly related to high-risk IPSS categories, show that, respectively, 4/9 and 4/13 cases bear the PI-PLC 1 deletion. On the contrary, in our series where only one patient was at high risk, none of the 23 patients showed a cryptic deletion of band 20p12.3.2 Similar observations were recently done by Verburgh et al.4 who failed to detect a deletion of the PI-PLC 1 gene in a series of 33 MDS patients with normal karyotype, of which two belonged to the high-risk group as defined by the IPSS. In the same way, no deletion was observed in the 10 low-risk MDS patients reported in the comment of Lo Vasco et al.1 All these data indicate that the deletion of the PI-PLC 1 gene probably will not be detected in MDS patients with normal karyotype and low or intermediate IPSS risks. Conversely, in the high-risk group, the deletion could be frequent (about one-third of the reported cases till now) and associated with alterations of the signalling pathways and short survivals.