ATM and systemic lupus erythematosus: For example, low expresser patient 13, the patient with the compound pathogenic ATM genotype and the lowest level of ATM protein (~10%) and very low ATM kinase activity and a high ICA count had an average SF2 value of 41.6 which was higher than the other 3 low ATM expresser patients 10, 11 and 16 (22.4, 25.7 and 33.8, respectively) and comparable to that for non-reactor controls (39.5 ± 5.98) and higher compared with the SF2 value for women with SLE (33.0 ± 3.19) (Table 2).