Common chitotriosidase duplication gene polymorphism and clinical outcome status in sarcoidosis

Chitotriosidase has been found to be useful as a sarcoidosis biomarker. In patients with better outcome lower values were observed. Some subjects have 24-base pair duplication in the chitotriosidase gene (CHIT1) that results in the production of inactive enzyme. This might influence the outcome of sarcoidosis and account for described observations.

The aim of this study was to correlate common CHIT1 duplication polymorphism and clinical outcome status in sarcoidosis (COS).

This retrospective study comprised 180 patients with sarcoidosis. COS at 3, 5 and 10 years was determined and correlated with CHIT1 24-base pair duplication polymorphism. CHIT1 genotyping was done by the PCR method.

There was no significant correlation between CHIT1 24-base pair duplication polymorphism and COS at 3, 5 or 10 years but a subgroup analysis showed higher frequency of patients with Loefgren's syndrome (50% vs. 17.1%) and better COS in CHIT1 24-base pair duplication homozygotes vs. all other subjects in major COS groups (no, minimal and persistent disease) at 3 years (p=0.025) and borderline significant at 5 years (p = 0.090).

In this study no correlation between CHIT1 24-base pair duplication polymorphism and COS was shown, but possible protective role of homozygous condition for CHIT1 24-base pair duplication polymorphism is suggested.