1. Hematology Department, Hospital de l'Esperit Sant, Santa Coloma de Gramenet, Barcelona, Spain 08923.
2. Genetics, Hematology and Epidemiology Departments, Hospital de Sant Pau, Barcelona, Spain 08025.
3. Clinical Biochemistry Institute, Barcelona, Spain 08028.
4. Public Health Department, Generalitat de Catalunya, Barcelona, Spain 08028.
5. Instituto de Salud Carlos III, Madrid, Spain 28029.
6. nstituto de Salud Carlos III, Madrid, Spain 28029.