In addition, the spectrum of HPRT deletions observed in FA patients differs from that of healthy children: there is a high frequency of 3'-terminal deletions and a strikingly low proportion of V(D)J mediated events.
Great similarities were found between normal and FA cells with respect to the nature and location of point mutation at the HPRT gene; the high proneness to deletions remains one of the major instability features of FA.
Knowing that the cellular events allowing the detection of mutations at the HPRT and the GPA locus differ, our results emphasize the possible correlation between events of spontaneous loss of heterozygosity and genetic predisposition to cancer as observed in FA.