**Agnieszka Kempinska-Podhorodecka 1,\*, Monika Adamowicz 1, Mateusz Chmielarz 1, Maciej K. Janik 2, Piotr Milkiewicz 2,3 and Malgorzata Milkiewicz <sup>1</sup>**


Received: 20 June 2020; Accepted: 23 July 2020; Published: 27 July 2020

**Abstract:** Vitamin D deficiency has been associated with depressive symptoms and reduced physical functioning. The aim of the study was to characterize the relationship between polymorphisms of the vitamin D receptor (VDR) gene and the quality of life in patients with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC). Three polymorphisms of the *VDR* gene (*TaqI-rs731236*, *BsmI-rs1544410*, and *ApaI-rs7975232*) were analyzed in patients with AIH (*n* = 142) and PBC (*n* = 230) and in healthy individuals (*n* = 376). Patient quality of life was assessed by validated questionnaires such as Medical Outcomes Study Short-Form 36 (SF-36), State Trait Anxiety Inventory (STAI), Modified Fatigue-Impact Scale (MFIS), Patient-Health Questionnaire 9 (PHQ-9), and PBC-40. The *TaqI* C and *ApaI* A alleles are risk alleles in both AIH and PBC, and a significant dominance of the A allele in *BsmI* was observed in AIH patients. In terms of quality of life, the presence of the CC or CT *TaqI* genotype was associated with emotional reactions, including the fatigue and the cognitive skills of patients with PBC, whereas in the group of AIH patients, homozygotes CC of *TaqI*, AA of *BsmI*, and AA of *ApaI* had worse physical, social, emotional, and mental function. The genetic variations of *VDR* gene can influence individual susceptibility to develop chronic autoimmune liver diseases such as AIH and PBC and affect quality of life.

**Keywords:** autoimmune hepatitis; primary biliary cholangitis; vitamin D; health-related quality of life; mental well-being
