Abstract
The enzyme DNASE1 plays an important role in the hydrolysis of double-stranded DNA
and might be related to autoimmunity. Therefore, the authors hypothesized that patients
with autoimmune thyroid disease show a reduced expression of the DNASE1 gene. DNASE1 mRNA was quantitatively analyzed in 20 patients (10 with Hashimoto’s thyroiditis
and 10 with Graves’ disease) and 20 age- and sex-matched healthy controls by real-time
reverse transcription PCR in a lightcycler using SYBR-Green-format. For relative quantification,
the mRNA ratio of the DNASE1 gene to the house keeping gene β2-MICROGLOBULIN was used. The house keeping gene was proved not to be regulated by autoimmune thyroid
disease. The interassay coefficient of variation for patients and controls was 22.2%
and 15.6%, respectively, suggesting good reproducibility of measurements. The mean
expression of the DNASE1 mRNA in patients was 0.52±0.22 (range 0.18–0.99) and in controls 0.95±0.22 (0.66–1.43).
The expression level of the DNASE1 gene was strongly decreased in patients, amounting only 54.7% of that in controls
(p<0.001). The lowered expression level in patients was not related to age or sex.
This study demonstrated for the first time a downregulation of the DNASE1 mRNA expression in patients with autoimmune thyroid disease. This might result in
degrading less DNA from dying cells, thereby promoting the development of thyroid
autoimmunity.
Key words
DNASE1 gene - autoimmune thyroid disease - relative quantification - real-time PCR - human
