Abstract

Background: Fanconi anemia (FA) is a heterogeneous genetic disease, where twelve complementation groups have been already described. Identifying the complementation group in FA patients constitutes a direct procedure to confirm the diagnosis of the disease, and is required for the recruitment of these patients in gene therapy trials.

Objective: We aim to determine the subtype of FA patients in Spain, a Mediterranean country with a relatively high population (23%) of FA patients belonging to the gypsy ethnia.

Methods: Most patients could be subtyped by retroviral complementation approaches in peripheral blood T cells, although some mosaic patients were subtyped in cultured skin fibroblasts. Other approaches, mainly based on western blot analysis and generation of nuclear Rad51 and FANCJ foci were required for the subtyping of a minor number of patients.

Results and conclusions: From a total of 125 patients included in the Registry of FA, samples from 102 patients were available for subtyping analyses. In 89 cases the subtype could be determined and in 8 cases, exclusions of common complementation groups were made. Compared to other international studies, a skewed distribution of complementation groups was observed in Spain, where 80% of the families belonged to the FA-A complementation group. The high proportion of gypsy patients, all of them FA-A, and the absence of FA-C patients account for this characteristic distribution of complementation groups.